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This document provides information about a Java training module offered by Aims Tutorial, including their contact information, address, and an introduction to Java. It discusses Java's history and features such as being object-oriented, platform independent, simple, secure, architecturally neutral, portable, robust, multi-threaded, dynamic, and high performance. It also covers types of Java applications, different Java technology editions, and compares Java to C++.
![Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
manishsony4u@gmail.com
Introduction of java
Aims Tutorial
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H.No.:69/339 VT Road Ward 27,
Mansarovar Jaipur (Rajasthan) 302020
Contact No: +91-8947920041
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First java Program
public class FirstJava
{
public static void main(String[] args)
{
System.out.println("Welcome in Aims");
}
}
class: class is a keyword is used to declare classes in java
public: It is an access specifiers . Public means this function is visible to all.
static: static is used to make a function static. To execute a static function you
do not have to create an Object of the class. The main () method here is called
by jvm, without creating any object for class.
void: void is return type, meaning this function will not return anything.
main(): main() method is the most important method in a java program . this
is the method which is executed hence all logic must be inside the main()
method. If a java class is not having a main() method, it causes compilation
error.
System.out.println(): This is used to print anything on the consol like
printf()in c.
Steps to compile and Run FirstJava Program
Step: 1 Open a text editor like Notepad and write the code as above.
Step: 2 save the file as FirstJava.java
Step: 3Open command prompt and go to the directory where you saved your first java
program](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-11-320.jpg)
![Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
manishsony4u@gmail.com
Introduction of java
Aims Tutorial
Oriental Bank of Commerce
H.No.:69/339 VT Road Ward 27,
Mansarovar Jaipur (Rajasthan) 302020
Contact No: +91-8947920041
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Java Development Kit (JDK)
JDK is an acronym for Java Development Kit.
It physically exists. It contains JRE + the complete set of class file for all the java technology
package, which include basic language classes.GUI components classes, an advanced
collection API, and so no.
Java Virtual Machine (JVM)
It is an abstract machine or imaginary machine that is implemented by emulating it in
software on a real machine. Code for JVM is stored in .class file. It is a specification that
provides runtime environment in which java bytecode can be executed.
JVMs are available for many hardware and software platforms. JVM, JRE and JDK are
platform dependent because configuration of each OS differs. But, Java is platform
independent.
The JVM specification provides concrete definition for the implementation of the following:
an instruction set (equivalent to that of a center processing machine [CPU]), a register set,
the class file format, a runtime stack, a garbage-collector heap a memory area etc.
The JVM performs following main tasks:
Loads code
Verifies code
Executes code
Provides runtime environment
JVM Internal Architecture
It contains
1. Class loader: class loader loads all classes needed for the execution of a program. The class
loader adds security.
2. Memory area
1. Class (Method) Area: Class (Method) Area stores per-class structures such as the runtime
constant pool, field and method data, the code for methods.
2. Heap: It is the runtime data area in which objects are allocated.
3. Stack: It holds local variables and partial results, and plays a part in method invocation and
return.
4. Program counter Registers: PC (program counter) register. It contains the address of the
Java virtual machine instruction currently being executed.
5. Native Method Stack: It contains all the native methods used in the application.
3. Execution engine
It contains
1. A virtual processor
2. Interpreter: Read byte code stream the execute the instruction](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-13-320.jpg)
![Aims Tutorial
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H.No.:69/339 VT Road Ward 27,
Mansarovar Jaipur (Rajasthan) 302020
Contact No: +91-8947920041
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Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
manishsony4u@gmail.com
Tokens
Tokens
Each and every smallest individual unit in a program is known as tokens.
Tokens are the basic buildings blocks in language which are constructed together to
write a program.
The keywords, identifiers, constants, string literals, and operators are examples
of tokens. Punctuation characters such as brackets [ ], braces { }, parentheses ( ), and
commas (,) are also tokens.
1.Keywords
Keywords are those words whose meaning is already defined by language
There are 50 Keywords in java.
Keywords are also called as reserved words.
const and goto are two keywords which are reserved in java but not defined by
java language.
abstract continue goto package switch
assert default if private this
boolean do implements protected throw
break double import public throws
byte else instanceof return transient
case extern int short try
catch final interface static void
char finally long stricfp volatile
class float native super while
const for new synchronized](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-17-320.jpg)
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Mansarovar Jaipur (Rajasthan) 302020
Contact No: +91-8947920041
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Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
manishsony4u@gmail.com
Tokens
4. String literals
The set of characters represented as String literals. It is use “double
quotes”.
final String ch="Aims";
5. Boolean literals
The values true and false are treated as literals in java. When we assign a
value to a boolean variable is true or false.
final boolean bool=true;
4.Operator
Operator is the special symbols the perform the mathematical and logical manipulation.
Types of operator
1. Arithmetic operator
Operators which are used for arithmetical operation (+, -, *, /, and %) called
arithmetic operator.
Operator Meaning
+ Addition
- Subtraction
* Multiplication
/ Division
% Modulus
2. Relational operator
Operators are used to test the relation between two values called relational operator.
All relational operators are binary operators and therefore require two operands. A
relational expression returns false when the relation is false and a true when it is
true.
Relational Operators Meaning
< Less than
<= Less than or equal to
== Equal to
> Greater than
>= Greater than or equal to
! = Not equal to
public class RelationalOperatorsDemo
{ public static void main(String args[])
{
int x = 10, y = 5;
System.out.println("x > y : "+(x > y));
System.out.println("x < y : "+(x < y));
System.out.println("x >= y : "+(x >= y));
System.out.println("x <= y : "+(x <= y));
System.out.println("x == y : "+(x == y));
System.out.println("x != y : "+(x != y));
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-20-320.jpg)
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H.No.:69/339 VT Road Ward 27,
Mansarovar Jaipur (Rajasthan) 302020
Contact No: +91-8947920041
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By:Manish Swarnkar
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Tokens
3. Logical operator
Operators which are used to combine one or more relational expression called logical
operator.
Operators Meaning operation
|| OR a||b is true
&& AND a&&b is false
! NOT (!a) is false
public class LogicalOperatorsDemo
{
public static void main(String args[]) {
boolean x = true;
boolean y = false;
System.out.println("x & y : " + (x & y));
System.out.println("x && y : " + (x && y));
System.out.println("x | y : " + (x | y));
System.out.println("x || y: " + (x || y));
System.out.println("x ^ y : " + (x ^ y));
System.out.println("!x : " + (!x));
}
}
4. Bitwise operator
These operators are used to perform bit operations. Decimal values are converted into
binary values which are the sequence of bits and bit wise operators work on these bits.
Bit wise operators in java are & (bitwise AND), | (bitwise OR), ~ (bitwise OR), ^ (XOR),
<< (left shift) and >> (right shift).
Operator Meaning
& Bitwise AND
| Bitwise OR
^ Bitwise XOR
~ One ‘Complement
>> Bitwise right shift
<< Bitwise left Shift
Truth Table of Bitwise operator
x y x|y x&y x^y
0 0 0 0 0
0 1 1 0 1
1 0 1 0 1
1 1 1 1 0](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-21-320.jpg)
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Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
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Tokens
public class BitwiseOperatorsDemo
{
public static void main(String args[])
{
int x = 0xFAEF; //1 1 1 1 1 0 1 0 1 1 1 0 1 1 1 1
int y = 0xF8E9; //1 1 1 1 1 0 0 0 1 1 1 0 1 0 0 1
int z; System.out.println("x & y : " + (x & y));
System.out.println("x | y : " + (x | y));
System.out.println("x ^ y : " + (x ^ y));
System.out.println("~x : " + (~x));
System.out.println("x << y : " + (x << y));
System.out.println("x >> y : " + (x >> y));
System.out.println("x >>> y : " + (x >>> y));
}
}
5. Ternary operator
Operator that performs operation on three operands called ternary operator.
Conditional Operator
The conditional operator ? : is called ternary operator as it requires three
operands.
Syntax:
Conditional Exp? Exp1: Exp2
If the value of conditional expression is true then the exp1 is evaluated, otherwise exp2 is
evaluated.
public class TernaryOperatorsDemo
{
public static void main(String args[]) {
int x = 10, y = 12, z = 0;
z = x > y ? x : y;
System.out.println("z : " + z);
}
}
6. Assignment operator
Operator ('=') which is used for assigning a value to a variable is called assignment
operator. This operator takes the expression on its right-hand-side and places it into
the variable on its left-hand-side.
For example: m = 5;
Operator Example Equivalent to
+ = A + = 2 A = A + 2
- = A - = 2 A = A - 2
% = A % = 2 A = A % 2
/= A/ = 2 A = A / 2
*= A * = 2 A = A * 2](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-22-320.jpg)
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Tokens
7. Increment or decrement operator
Operator which perform operation only on one operand are called Unary operator.
1. Increment Operator
++ Operator increment the value of a variable by 1 is called increment operator.
Pre-increment
++ is written before variable name. Value is incremented first then
incremented value is used in expression.
Ex:
public class IncPre
{
public static void main(String args[]) {
int i, a=5;
i=++a;
System.out.println(i);
}
}OUTPUT: 6
Post-increment
++ is written after variable name. Value is assigned to expression after that the
value is increment.
Ex:
public class IncPre
{
public static void main(String args[]) {
int i, a=5;
i=a++;
System.out.println(i);
}
}OUTPUT:5
2. Decrement Operator
-- Operator decrement the value of a variable by 1 is called decrement operator.
Pre-decrement
-- is written before variable name. Value is decremented first then
decremented value is used in expression.
Ex:
public class IncPre
{
public static void main(String args[]) {
int i, a=5;
i=--a;
System.out.println(i);
}
}OUTPUT: 4](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-23-320.jpg)
![Aims Tutorial
Oriental Bank of Commerce
H.No.:69/339 VT Road Ward 27,
Mansarovar Jaipur (Rajasthan) 302020
Contact No: +91-8947920041
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Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
manishsony4u@gmail.com
Tokens
Post-decrement
-- is written after variable name. Value is assigned in expression then the
decrement the value.
Ex:
public class IncPre
{
public static void main(String args[]) {
int i, a=5;
i=a--;
System.out.println(i);
}
}OUTPUT:5
5.Separator
The separators define the structure of a program. The separators are used parentheses (
), braces { }, the period (.) and (;) semicolon.
Comments
Comments are special part of the program, to describe or explain the code which make
easy to understand.
Comments are those lines which are not read by the compilers.
Types of Comments
1. Single line comments
Single line comments starts with two forward slash (//)
It useful when only single lines are commented.
final int a=5// a is constants variable
2. Multiline comments
Multiline comments are starts with forward slash/ and after that star (*) and
the text or comment line put then again star(*) put the again forward slash(/)
put to comment .
It is useful when we comment multiple line in program.
3. Document comment
/** document comment*/
This is document comment it described the author and other information
about a program. The JDK javadoc tool uses doc comment for
automatically generated documentation.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-24-320.jpg)
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Java Tutorial
By:Manish Swarnkar
Contact No:9887474850
manishsony4u@gmail.com
Class
Class
“Class is a user defined data types, which holds variables and , which can be accessed and
used by creating instance of that class.”
Class is just a blue print, which declare and defined variables and methods. All objects
of this class will share these data member and function.
About Class:
1. Class name start with an uppercase letter. If class name is made then one word, the
first letter of each word must be in uppercase.
Ex:- Class Study, class AimsTutorial
2. Objects of the class holds separate copies of data member. We can create as many
objects of a class as we need.
How to declare class:
Syntax:
public class Class_Name
{
variables;
methods( );
public static void main(String[] args)
{
Class_Name obj=new Class_Name()
}
};
Example:
public class Aims
{
int i=10;
public static void main(String[] args)
{
Aims a1=new Aims();
System.out.println(a1.i);
}
}
Output: 10;
Objects
Objects are the variable which declare using class name, it holds the data variable, declared in
the class and the member function works on these class objects.
How to declare objects:
public class Abc
{
int x=10;
void display( )
{
System.out.println(x);
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-27-320.jpg)
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Class
public static void main(String[] args)
{
Abc obj=new Abc();
Obj.display();
}
}
Output:10
Each object has different data variables.
Object are initialized using special methods are called constructor.
A class can contain any of the following variable types.
Local variables − Variables which defined inside methods, constructors or blocks are
called local variables. The variable will be declared and initialized within the method
and the variable will be destroyed when the method has completed.
class Test
{
public static void main(String[] args)
{
int a=10; Local variables
int b=20;
System.out.println(a+b);
}
}
Instance variables − Instance variables are variables within a class but outside any
method. These variables are initialized when the class is instantiated. Instance
variables can be accessed from inside any method, constructor or blocks of that
particular class.
class Test
{
int a=10;
int b=20;
void add()
{
System.out.println(a+b);
}
public static void main(String[] args)
{
Test t=new Test();
System.out.println(t.a+t.b);
t.add();
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-28-320.jpg)
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Array
Static variable or Class variables − Class variables are variables declared within a
class, outside any method, with the static keyword.
class Test
{
static int b=20;
public static void main(String[] args)
{
System.out.println(b);//20
}
}
Arrays:-
1) Array is a final class inheritance is not possible.
2) Arrays are used to store the multiple numbers of elements of single type.
3) The length of the array is established at the time of array creation. After creation the length
is fixed.
Root structure:-
java.lang.Object
+--java.lang.reflect.Array
public final class Array extends Object
single dimensional array declaration:-
int[] a;
int []a;
int a[];
declaration & instantiation & initialization :-
approach 1:- int a[]={10,20,30,40};
approach 2:- int[] a=new int[100];
a[0]=10;
a[1]=20;
a[2]=30;
a[4]=40;
10 20 30 40 50 60 70 80 90
Ex:-printing the array elements
class Test
{
public static void main(String[] args)
{
int[] a={10,20,30,40};
System.out.println(a[0]);
System.out.println(a[1]);
System.out.println(a[2]);
System.out.println(a[3]);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-29-320.jpg)
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Mansarovar Jaipur (Rajasthan) 302020
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Array
Ex:-printing the array elements by using for loop
class Test
{
public static void main(String[] args)
{
int[] a={10,20,30,40};
for (int i=0;i<a.length;i++)
{
System.out.println(a[i]);
}
}
}
declaration of two dimensional array:-
int[][] a;
int [][]a;
int a[][];
int []a[];
Ex:-
class Test
{
public static void main(String[] args)
{
int[][] a={{10,20,30},{40,50,60}};
System.out.println(a[0][0]);//10
System.out.println(a[1][0]);//40
System.out.println(a[1][1]);//50
}
}
Methods (behaviors):-
1) Methods are used to provide the business logic of the project.
2) The methods like a functions in C-language called functions, in java language is called
methods.
3) Inside the class it is possible to declare any number of methods based on the developer
requirement.
4) As a software developer while writing method we have to fallow the coding standards like
the method name starts with lower case letters if the method contains two words every inner
word also starts uppercase letter.
5) It will improve the reusability of the code. By using methods we can optimize the code.
Syntax:-
[modifiers-list] return-Type Method-name (parameter-list)throws Exception
Ex:-
public void m1()
public void m2(int a, int b)
Method Signature:-
The name of the method and parameter list is called Method Signature. Return type and
modifiers list not part of a method signature.
Ex:- m1(int a,int b)------Method Signature
m2();------------------Method signature](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-30-320.jpg)
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Array
There are two types of methods:-
Instance method
Method which are declare and defined inside a class and without static keyword and
called using object.
class Test
{
void display()
{
System.out.println("Aims Tutorial");
}
public static void main(String[] args)
{
Test t=new Test();
t.display();
}
}
Static method
Method which are declare and defined inside a class and with static keyword and
called using classname.
class Test
{
Static void display()
{
System.out.println("Aims Tutorial");
}
public static void main(String[] args)
{
Test.display();
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-31-320.jpg)
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Constructor
Heap memory Stack memory
1) It is used to store the objects 1) It is used to store the function calls and
local variables.
2) We are getting outOfMemoryError 2) If the there is no memory in the stack to
store method calls or local variables the JVM
will throw the StackOverflowError.
3) Having more memory compared with the
stack memory.
4) Heap memory is also known as public
memory. This is applicable all the objects.
This memory is shared by all threads.
5)the objects are created in the heap memory
with the help of new operator
3) Stack memory is very less memory when
compared with the heap memory
4) Stack memory also known as private
memory. This is applicable only for owners.
5) Destroy when the method is completed.
Jvm is creating stack memory
Constructor
Constructor is a special type of method which has same as class that is used to initialize the
object. Constructor is called at the time of object creation. It constructs the value or provides
data for the object that is why it is known as constructor.
Rules for creating constructor
1. Constructor name must be same as its class name.
2. Constructor must have no return type.
Types of constructor
1. Default constructor.
A Constructor that have no parameter is known as default constructor.
Purpose of default constructor
Default constructor provide the default value to the object 0,null etc depending on the
type.
class Bike
{
public static void main(String args[])
{
Bike b=new Bike();
}
Bike()
{
System.out.println(“Default constructor is created”);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-32-320.jpg)
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Constructor
2. Parameterized constructor.
A Constructor that has parameter is known as parameterized constructor.
Why use parameterized Constructor
parameterized constructor provide the different values to the distinct object
class Square
{
public static void main(String args[])
{
Square b=new Square (5);
}
Square(int n)
{
System.out.println(n*n);
}
}
this heyword:-
This keyword is used to represent
1. Current class variables.
2. Current class methods.
3. Current class constructors.
class Test
{
int a=10;
int b=20;
void add(int a,int b)
{
System.out.println(a+b);
System.out.println(this.a+this.b);
}
public static void main(String[] args)
{
Test t=new Test();
t.add(100,200);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-33-320.jpg)
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Inheritance
1. Single Inheritance
public class Shap
{
int width;
int height;
void setdata(int w, int h)
{
width=w;
height=h;
}
}
class Rectangle extends Shap
{
int getArea()
{
return(width*height);
}
public static void main(String[] args)
{
Rectangle Rect;
Rect.setdata(5,7);
System.out.prinln(“Total Area="+Rect.getArea());
}
2. Multilevel
publc class Student
{
int rollno;
void read(int rollno)
{
this.rollno=rollno;
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-37-320.jpg)
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Inheritance
class Marks extends Student
{
int m1, m2, m3;
void getMarks(int m1,int m2,int m3)
{
this.m1=m1;
this.m2=m2;
this.m3=m3;
}
}
class Result extends Marks
{
int total;
void process()
{
total=m1+m2+m3;
}
void print()
{
System.out.prinln(“Total result="+total);
}
public static void main(String[] args)
{
Result R;
R.read();
R.getMarks();
R.process();
R.print();
}
}
Output: Enter RollNo=234
Enter Marks in Sub1=20
Enter Marks in Sub2=30
Enter Marks in Sub3=40
Total result=90](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-38-320.jpg)
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Inheritance
3. Hierarchal
public class Shap
{
int width;
int height;
void setdata(int w, int h)
{
width=w;
height=h;
}
}
public class Rectangle extends Shap
{
int getArea()
{
return width*height;
}
}
public class Triangle extends Shap
{
int getArea()
{
return (width*height)/2;
}
public static void main(String[] args)
{
Rectangle rect;
Triangle tri;
rect.setdata(5,7);
tri.setdata(5,8);
System.out.println(“Area of Rectangle="+rect.getArea());
System.out.prinln(“Area of Triangle="+tri.getArea());
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-39-320.jpg)
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Polymorphism
POLYMORPHISM
1) One thing can exhibits more than one form called polymorphism.
2) The ability to appear in more forms.
3) Polymorphism is a Greek word poly means many and morphism means forms.
Types of Polymorphism
1. Compile Time Polymorphism (Early binding, Static binding)
2. Run Time Polymorphism (Late binding, Dynamic binding)
Ex:-Method Overloading Ex:-Method Overriding
A. Method overloading ( Compile Time Polymorphism ,Early binding, Static binding)
If any class has multiple method with same name but different parameters then they
are said to be overloaded.
Function overloading allows to use the same name for different function to
performed either same or different action in the same class.
Method overloading is usually used to enhance the readability of the program. If you
have to perform one single operation but with different number or types of
arguments, then you can simply overload the method There are two types of
method overloading in java
1. By Changing number of arguments
Class Cal
{
void add(int a, int b)
{
System.out.prinln(a+b);
}
void add(int a, int b, int c)
{
System.out.prinln(a+b+c);
}
public static void main(String args[])
{
Cal C1=new Cal();
C1.add(2,4);
C1.add(2,3,4);
}
}
2. By having different types of arguments
Class Cal
{
void add(int a, int b)
{
System.out.prinln(a+b);
}
void add(float a, float b)](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-40-320.jpg)
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Polymorphism
{
System.out.prinln(a+b);
}
public static void main(String args[])
{
Cal C1=new Cal();
C1.add(2,4);
C1.add(2.5f,3.4f);
}
}
B. Constructor overloading
Just like Method constructor can be overloaded.
We can define multiple constructors with different parameters to overload.
Class Cal
{
void Cal(int a, int b)
{
System.out.prinln(a+b);
}
void Cal(int a, int b, int c)
{
System.out.prinln(a+b+c);
}
public static void main(String args[])
{
Cal C1=new Cal(2,3);
Cal C2=new Cal(3,4,5);
}
}
B. Method Overriding
If we inherit a class into the derived class and provide a definition for one of the
base class’s method again. The method is said to be overriding.
Requirement for method overriding
Inheritance should be there. method overriding cannot be done within a class, for
this we require a derived class and a base class.
method signature should be same in base class and derived class.
class Base
{
void show()
{
System.out.prinln(“Base Class”+”t");
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-41-320.jpg)
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Polymorphism
class Derived extends Base
{
void show()
{
System.out.prinln("Derived Class");
}
public static void main(String[]args)
{
Base B=new Base();
Derived D=new Derived();
B.show();
D.show();
}
}
Output:
Base Class
Derived Class
In the above example, we are calling the overridden function using Base Class and Derived
Class object. Base class object call base class version of function and derived class’s object
call Derived class version of function.
Difference between method overloading and method overriding in java
There are many differences between method overloading and method overriding in java. A list of
differences between method overloading and method overriding are given below:
No. Method Overloading Method Overriding
1)
Method overloading is used to increase the readability of
the program.
Method overriding is used to provide
the specific implementation of the
method that is already provided by its
super class.
2) Method overloading is performed within class.
Method overriding occurs in two classes
that have IS-A (inheritance)
relationship.
3)
In case of method overloading, parameter must be
different.
In case of method overriding,
parameter must be same.
4)
Method overloading is the example of compile time
polymorphism.
Method overriding is the example of
run time polymorphism.
5)
In java, method overloading can't be performed by
changing return type of the method only. Return type
can be same or different in method overloading. But you
must have to change the parameter.
Return type must be same or covariant
in method overriding.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-42-320.jpg)
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Abstraction
ABSTRACTION
Hiding the internal implementation details and highlighting the essential functionality to the
user this mechanism is called abstraction.
Ex:
a. Bank ATM Screens (Hiding thee internal implementation and highlighting set of services
like withdraw, money transfer, mobile registration).
b. Mobile phones (The mobile persons are hiding the internal circuit implementation and
highlighting touch screen).
Abstraction concepts are implemented in java by abstract class and interface
1. Abstract Class
Abstract class is a java class which contains at least one abstract method.
To specify the particular class is abstract and particular method is abstract method by
using abstract modifier.
For the abstract classes it is not possible to create an object. Because it contains the
unimplemented methods.
For any class if we don’t want instantiation then we have to declare that class as abstract
i.e., for abstract classes instantiation (creation of object) is not possible.
abstract class Test
{
abstract void m3();
}
Abstract class:-
class Test
{
abstract void m1();
abstract void m2();
abstract void m3();
}
abstract class Add
{
abstract void add(int a, int b);
}
class Cal extends Add
{
void add(int a, int b)
{
System.out.println(a+b);
}
public static void main(String[] args)
{
Cal C1=new Cal();
C1.add(3,4);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-43-320.jpg)
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Abstraction
Abstract methods:-
The method which is having declaration but not implementations such type of methods are
called abstract Method. Hence every abstract method should end with “;”.
The child classes are responsible to provide implementation for parent class abstract
methods.
public abstract Add
{
abstract void add(int a, int b);//it is abstract method which has no definition
}
class Cal
{
void add(int a, int b)
{
System.out.println(a+b);
}
public static void main(String[] args)
{
Cal C1=new Cal();
C1.add(3,4);
}
}
2. Interface
1. Interface is also one of the type of class it contains only abstract methods.
2. For the interfaces also .class files will be generated.
3. Each and every interface by default abstract hence it is not possible to create an
object.
4. Interfaces not alternative for abstract class it is extension for abstract classes.
5. 100 % pure abstract class is called interface.
6. The Interface contains only abstract methods means unimplemented methods.
7. Interfaces giving the information about the functionalities it are not giving the
information about internal implementation.
8. To provide implementation for abstract methods we have to take separate class that
class we can called it as implementation class for that interface.
9. Interface can be implemented by using implements keyword.
10. For the interfaces also the inheritance concept is applicable.
Syntax:-
Interface interface-name
Ex:- interface it1
Note: -
if we are declaring or not By default interface methods are public abstract
interface it1 abstract interface it1
{ {
Void m1(); Both are same public abstract void m1();
Void m2(); public abstract void m2();
} }](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-44-320.jpg)
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Abstraction
interface Cal
{
void add(int a, int b);
void sub(int a, int b);
}
class Solution implements Cal
{
void add(int a, int b)
{
System.out.prinln(a+b);
}
void sub(int a, int b)
{
System.out.prinln(a-b);
}
public static void main(String[] args)
{
Solution S1=new Solution()’
S1.add();
S1.sub();
}
}
Adaptor class:-
It is a intermefdiate class between the interface and user defined class. And it contains empty
implementation of interface methods.
Limitation of interface advantage of adaptor classes
interface it
{
void m1();
void m2();
;
;
void m100()
}
Class Test implements it
{
Must provide implementation of 100 methods otherwise compiler raise compilation
error
}
interface it
{
void m1();
void m2();
;
;
void m100() ;
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-45-320.jpg)
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Encapsulation
Encapsulation
The process of binding the data and code as a single unit is called encapsulation.
We are able to provide more encapsulations by taking the private data(variables) members.
To get and set the values from private members use getters and setters to set the data and to
get the data.
Ex:-
class Encapsulation
{
private int sid;
private int sname;
public void setSid(int x)
{
this.sid=sid;
}
public int getSid()
{
return sid;
}
public void setSname(String sname)
{
this.sname=sname;
}
public String getSname()
{
return sname;
}
}
To access encapsulated use fallowing code:-
class Test
{
public static void main(String[] args)
{
Encapsulation e=new Encapsulation();
e.setSid(100);
e.setSname("ratan");
int num=e.getSid();
String name=e.getSname();
System.out.println(num);
System.out.println(name);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-47-320.jpg)
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Super key-word
Super Key-word
Super:- Super keyword is used to represent
1) Call the Super class variable.
2) Call the super class constructor.
3) Call the super class methods.
Super keyword is not required
class Parent
{
int a=10;
int b=20;
}
class Child extends Parent
{
int x=100;
int y=200;
void add(int i,int j)
{
System.out.println(i+j);
System.out.println(x+y);
System.out.println(a+b);
}
public static void main(String[] args)
{
Child c=new Child();
c.add(1000,2000);
}
}
Super keyword is required
class Test1
{
int a=10;
int b=20;
};
class Test extends Test1
{
int a=100;
int b=200;
void add(int a,int b)
{
System.out.println(a+b);
System.out.println(this.a+this.b);
System.out.println(super.a+super.b);
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-48-320.jpg)
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Super key-word
public static void main(String[] args)
{
Test t=new Test();
t.add(1000,2000);
}
}
Command Line Arguments:-
The arguments which are passed from command prompt is called command line arguments.
We are passing command line arguments at the time program execution.
Ex1:-
class Test
{
public static void main(String[] args)
{
System.out.println(args.length);
System.out.println(args[0]);
System.out.println(args[1]);
}
}
Compilation : Javac Test.java
Execution : java Test a b c //a,b,c are the command line arguments
Output : 3
a
b
Modifiers
Modifiers are the keyword which define the accessibility or scope of a variable , class method
in the program.
1. Public
This is the modifier applicable for classes, methods and variables (only for
instance and static variables but not for local variables).
If a class is declared with public modifier then we can access that class from
anywhere (within the package and outside of the package).
If we declare a member(variable) as a public then we can access that member
from anywhere but Corresponding class should be visible i.e., before checking
member visibility we have to check class visibility.
Ex:-
public class Test // public class can access anywhere
{
public int a=10; //public variable can access any where
public void m1() //public method can access any where
{
System.out.println("public method access in any package");
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-49-320.jpg)
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Modifiers
public static void main(String[] args)
{
Test t=new Test();
t.m1();
System.out.println(t.a);
}
}
2. Default:-
This is the modifier applicable for classes, methods and variables (only for
instance and static variables but not for local variables).
If a class is declared with <default> modifier then we can access that class only
within that current package but not from outside of the package.
Default access also known as a package level access.
The default modifier in the java language is default.
class Test
{
void m1()
{
System.out.println("m1-method");
}
void m2()
{
System.out.println("m2-method");
}
public static void main(String[] args)
{
Test t=new Test();
t.m1();
t.m2();
}
}
in the above program we are not providing any modifier for the methods and classes
at that situation the default modifier is available for methods and classes that is default
modifier. Hence we can access that methods and class with in the package.
3. Private:-
Private is a modifier applicable for methods and variables. If a member
declared as private then we can access that member only from within the
current class.
If a method declare as a private we can access that method only within the
class. it is not possible to call even in the child classes also.
class Test
{
private void m1()
{
System.out.println("we can access this method only with in this class");
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-50-320.jpg)
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Modifiers
public static void main(String[] args)
{
Test t=new Test();
t.m1();
}
}
4. Protected :-
If a member declared as protected then we can access that member with in the
current package anywhere but outside package only in child classes.
But from outside package we can access protected members only by using
child reference. If we try to use parent reference we will get compile time error.
Members can be accesses only from instance area directly i.e., from static area
we can’t access instance members directly otherwise we will get compile time
error.
Ex:-demonstrate the user defined packages and imports.
Aims project source file:-
package calculator;
public class Cal
{
protected void add(int a, int b)
{
System.out.println(a+b);
}
protected void sub(int a, int b)
{
System.out.println(a-b);
}
protected void multi(int a, int b)
{
System.out.println(a*b);
}
}
import calculator.Cal;
public class Solution extends Cal
{
public static void main(String[] args)
{
Solution S1=new Solution();
S1.add(3,4);
S1.sub(3,2);
S1.multi(3,5);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-51-320.jpg)
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String
String
1) String is a final class it is present in java.lang package.
2) String is nothing but a group of characters or character array.
3) Once we are creating String object it is not possible to do the modifications on existing
object called immutability nature.
Constructors of string class:-
1) String str=new String(java.lang.String);
This constructor takes the String as a argument.
Ex:-
String str=new String(“Aims”);
System.out.println(str);//Aims
2) Stirng str=new String(char[]);
This constructor take the array of characters as a argument.
Ex:-
char[] ch={'a','b','c','d'};
String str1=new String(ch);
System.out.println(str1); //abcd
3) String str=new String(char[] ,int ,int );
This contractor takes the array of characters with starting index and ending index. First int
represent the starting position Second int represent the ending position.
Ex:-
char[] ch={'a','b','c','d'};
String str1=new String(ch,1,3);
System.out.println(str1);//bcd
Ex:-
class Test
{
public static void main(String[] args)
{
String str="Manish";
System.out.println(str); //Manish
String str1=new String("Manish");
System.out.println(str1); //Manish
String str2=new String(str1);
System.out.println(str2);
char[] ch={'a','i','m','s'};
String str3=new String(ch);
System.out.println(str3); //aims
char[] ch1={'t','u','t','o','r','i','a',’l’};
String str4=new String(ch1,1,5);
System.out.println(str4); //utorial
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-52-320.jpg)
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String
String is immutability nature:-
Once we are creating string object it is not possible to do the modifications on the existing
object is called immutability nature.
public class Test
{
public static void main(String[] args)
{
String str1=new String("Aims");
str1.concat("Tutorial”);
System.out.println(str1);
}
}
OUTPUT: Aims
String class Methods
Method Description
1 char charAt(int index) returns char value for the particular index
2 int length() returns string length
3 String concat(String str) concatenates specified string
4 int indexOf(int ch) returns specified char value index
5 String toLowerCase() returns string in lowercase.
6 String toUpperCase() returns string in uppercase.
7 String trim() removes beginning and ending spaces of this string.
8 static String valueOf(int value) converts given type into string. It is overloaded.
String charAt()
The java string charAt() method returns a char value at the given index number. The
index number starts from 0
public class CharAtExample
{
public static void main(String args[])
{
String name="AimsTutorial";
char ch=name.charAt(4); //returns the char value at the 4th index
System.out.println(ch);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-53-320.jpg)
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String
}
}
String length()
The java string length() method length of the string. It returns count of total number of characters.
The length of java string is same as the unicode units of the string.
public class LengthExample
{
public static void main(String args[])
{
String s1="java";
String s2="python";
System.out.println("string length is: "+s1.length());
//10 is the length of javatpoint string
System.out.println("string length is: "+s2.length());
//6 is the length of python string
}
}
String concat()
The java string concat() method combines specified string at the end of this string. It returns
combined string. It is like appending another string.
public class ConcatExample
{
public static void main(String args[])
{
String s1="java string";
s1.concat("is immutable");
System.out.println(s1);
s1=s1.concat(" is immutable so assign it explicitly");
System.out.println(s1);
}
}
String indexOf()
The java string indexOf() method returns index of given character value or substring. If it is
not found, it returns -1. The index counter starts from zero.
public class IndexOfExample
{
public static void main(String args[])
{
int index4=s1.indexOf('s');//returns the index of s char value
System.out.println(index4);//3
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-54-320.jpg)
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String
String toLowerCase()
The java string toLowerCase() method returns the string in lowercase letter. In other
words, it converts all characters of the string into lower case letter.
public class StringLowerExample
{
public static void main(String args[])
{
String s1="AMIS TUTORIAL";
String s1lower=s1.toLowerCase();
System.out.println(s1lower);
}
}
String toUpperCase
The java string toUpperCase() method returns the string in uppercase letter. In other
words, it converts all characters of the string into upper case letter.
public class StringUpperExample
{
public static void main(String args[])
{
String s1="hello string";
String s1upper=s1.toUpperCase();
System.out.println(s1upper);
}
}
String trim
The java string trim() method eliminates leading and trailing spaces. The unicode value of
space character is 'u0020'. The trim() method in java string checks this unicode value before
and after the string, if it exists then removes the spaces and returns the omitted string.
public class StringTrimExample
{
public static void main(String args[])
{
String s1=" hello student ";
System.out.println(s1+"welcome");//without trim()
System.out.println(s1.trim()+"in aims");//with trim()
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-55-320.jpg)
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String
StringBuffer
1. String Buffer is a class present in the java.lang package.
2. StringBuffer is a final class so it can’t be inherited.
3. StringBuffer is a mutable class so it is possible to change the content in the same location.
4. StringBuffer .equals() method is used for reference comparison.
What is mutable string
A string that can be modified or changed is known as mutable string. StringBuffer and
StringBuilder classes are used for creating mutable string.
Constructors:-
1. StringBuffer sb=new StringBuffer();
2. StringBuffer sb1=new StringBuffer(int capacity);
3. StringBuffer sb2=new StringBuffer(String str);
1) StringBuffer append() method
The append() method concatenates the given argument with this string.
class A
{
public static void main(String args[])
{
StringBuffer sb=new StringBuffer("Hello ");
sb.append("Java");//now original string is changed
System.out.println(sb);//prints Hello Java
}
}
2) StringBuffer insert() method
The insert() method inserts the given string with this string at the given position.
class A
{
public static void main(String args[])
{
StringBuffer sb=new StringBuffer("Hello ");
sb.insert(1,"Java");//now original string is changed
System.out.println(sb);//prints HJavaello
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-56-320.jpg)
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String
3) StringBuffer replace() method
The replace() method replaces the given string from the specified beginIndex and endIndex.
class A
{
public static void main(String args[])
{
StringBuffer sb=new StringBuffer("Hello");
sb.replace(1,3,"Java");
System.out.println(sb);//prints HJavalo
}
}
4) StringBuffer delete() method
The delete() method of StringBuffer class deletes the string from the specified beginIndex to
endIndex.
class A
{
public static void main(String args[])
{
StringBuffer sb=new StringBuffer("Hello");
sb.delete(1,3);
System.out.println(sb);//prints Hlo
}
}
5) StringBuffer reverse() method
The reverse() method of StringBuilder class reverses the current string.
class A
{
public static void main(String args[])
{
StringBuffer sb=new StringBuffer("Hello");
sb.reverse();
System.out.println(sb);//prints olleH
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-57-320.jpg)
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String
6) StringBuffer capacity() method
The capacity() method of StringBuffer class returns the current capacity of the buffer. The
default capacity of the buffer is 16. If the number of character increases from its current
capacity, it increases the capacity by (oldcapacity*2)+2. For example if your current capacity
is 16, it will be (16*2)+2=34.
class A
{
public static void main(String args[])
{
StringBuffer sb=new StringBuffer();
System.out.println(sb.capacity());//default 16
sb.append("Hello");
System.out.println(sb.capacity());//now 16
sb.append("java is my favourite language");
System.out.println(sb.capacity());//now (16*2)+2=34 i.e (oldcapacity*2)+2
}
}
Java StringBuilder class
Java StringBuilder class is used to create mutable (modifiable) string. The Java StringBuilder
class is same as StringBuffer class except that it is non-synchronized. It is available since JDK
1.5.
Important Constructors of StringBuilder class
1. StringBuilder(): creates an empty string Builder with the initial capacity of 16.
2. StringBuilder(String str): creates a string Builder with the specified string.
3. StringBuilder(int length): creates an empty string Builder with the specified capacity
as length.
Difference between String and StringBuffer
There are many differences between String and StringBuffer. A list of differences between
String and StringBuffer are given below:
No. String StringBuffer
1) String class is immutable. StringBuffer class is mutable.
2) String is slow and consumes more memory when you
concat too many strings because every time it creates new
StringBuffer is fast and consumes
less memory when you cancat](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-58-320.jpg)
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String
instance. strings.
3)
String class overrides the equals() method of Object class.
So you can compare the contents of two strings by equals()
method.
StringBuffer class doesn't override
the equals() method of Object class.
Difference between StringBuffer and StringBuilder
There are many differences between StringBuffer and StringBuilder. A list of differences between
StringBuffer and StringBuilder are given below:
No. StringBuffer StringBuilder
1)
StringBuffer is synchronized i.e. thread safe. It
means two threads can't call the methods of
StringBuffer simultaneously.
StringBuilder is non-synchronized i.e. not thread
safe. It means two threads can call the methods of
StringBuilder simultaneously.
2) StringBuffer is less efficient than StringBuilder. StringBuilder is more efficient than StringBuffer.
Java toString() method
If you want to represent any object as a string, toString() method comes into existence.
The toString() method returns the string representation of the object.
If you print any object, java compiler internally invokes the toString() method on the object. So
overriding the toString() method, returns the desired output, it can be the state of an object etc.
depends on your implementation.
class Student
{
int rollno;
String name;
String city;
Student(int rollno, String name, String city)
{
this.rollno=rollno;
this.name=name;
this.city=city;
}
public static void main(String args[])
{
Student s1=new Student(101,"Raj","lucknow");
Student s2=new Student(102,"Vijay","ghaziabad");
System.out.println(s1.toString);
System.out.println(s2);//compiler writes here s2.toString()
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-59-320.jpg)
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Wrapper Classes
Wrapper classes hierarchy
The main importance of wrapper classes:-
1. To convert a data types into the object means we are giving object from data types by
using constructor.
2. To convert String into the data types by using parsexxx() method
Utility methods:-
1. valueOf()
2. xxxValue()
3. parsexxx()
1) valueOf():-
By using valueof() we are creating wrapper object and it is a alternative to the constructor.
class Test
{
public static void main(String[] args)
{
//by using constructor converting String/primitive to wrapper object
Integer i=new Integer(10);
System.out.println(i);
//by using valueOf() converting String/primitive to the wrapper object
Boolean b=Boolean.valueOf("true");
System.out.println(b);
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-61-320.jpg)
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Wrapper Classes
XxxValue():-
by using XXXValue() method we are converting wrapper objects into the corresponding
primitive values
class Test
{
public static void main(String[] args)
{
Integer i=Integer.valueOf(150);
System.out.println("byte value :"+i.byteValue());//-106
System.out.println("short value :"+i.shortValue());//150
System.out.println("int value :"+i.intValue());//150
System.out.println("long value :"+i.longValue());//150
System.out.println("float value :"+i.floatValue());//150.0
System.out.println("double value :"+i.doubleValue());//150.0
Character c=new Character('s');
char ch=c.charValue();
System.out.println(ch);
Boolean b=new Boolean(false);
boolean bb=b.booleanValue();
System.out.println(bb);
}
}
parseXXX():-
by using above method we are converting String into the corresponding primitive.
class Test
{
public static void main(String[] args)
{
String str1="10";
String str2="20";
System.out.println(str1+str2);//1020
int a=Integer.parseInt(str1);
float f=Float.parseFloat(str2);
System.out.println(a+f);//30.0
}
}
Autoboxing and Autounboxing:-(introduced in the 1.5 version)
Until 1.4 version we are not allowed to place primitive in the wrapper and wrapper in the
place of primitive. The programmer is responsible person to do the explicit conversion
primitive to the wrapper and wrapper to the primitive.
Autoboxing:-
Integer i=10;
System.out.println(i);
The above statement does not work on the 1.4 and below versions. The auto conversion of the
primitive into the Wrapper object is called the autoboxing these conversions done by
compiler at the time of compilation.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-62-320.jpg)
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Wrapper Classes
Autounboxing:-
int a=new Integer(100);
System.out.println(a);
The auto conversion of the wrapper object to the primitive value is called autounboxing and
these conversions are done by compiler at the time of compilation.
Ex :-
class Test
{
static Integer i=10;//i is wrapper object
static int j;//j is primitive variable
static void print(int i)
{
j=i;
System.out.println(j);
}
public static void main(String[] args)
{
print(i);
System.out.println(j);
}
}
Automatic conversion of the primitive to wrapper and wrapper to the primitive:-](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-63-320.jpg)
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Java.io package
OutputStream class
OutputStream class is an abstract class. It is the super class of all classes representing an
output stream of bytes. An output stream accepts output bytes and sends them to some sink.
Useful methods of OutputStream
Method Description
1) public void write(int)throws
IOException
is used to write a byte to the current output
stream.
2) public void write(byte[])throws
IOException
is used to write an array of byte to the current
output stream.
3) public void flush()throws IOException flushes the current output stream.
4) public void close()throws IOException is used to close the current output stream.
OutputStream Hierarchy](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-65-320.jpg)
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Java.io package
FileOutputStream Class
Java FileOutputStream is an output stream used for writing data to a file.
If you have to write primitive values into a file, use FileOutputStream class. You can write
byte-oriented as well as character-oriented data through FileOutputStream class. But, for
character-oriented data, it is preferred to use FileWriter than FileOutStream.
FileOutputStream class methods
Method Description
protected void finalize() It is sued to clean up the connection with the file output stream.
void write(byte[] ary)
It is used to write ary.length bytes from the byte array to the
file output stream.
void write(byte[] ary, int off,
int len)
It is used to write len bytes from the byte array starting at offset
off to the file output stream.
void write(int b) It is used to write the specified byte to the file output stream.
FileChannel getChannel()
It is used to return the file channel object associated with the file
output stream.
FileDescriptor getFD()
It is used to return the file descriptor associated with the
stream.
void close() It is used to closes the file output stream.
Java FileOutputStream Example 1: write byte
import java.io.FileOutputStream;
public class FileOutputStreamExample {
public static void main(String args[]){
try{
FileOutputStream fout=new FileOutputStream("D:testout.txt");
fout.write(65);
fout.close();
System.out.println("success...");
}catch(Exception e){System.out.println(e);}
}
}
Output:
Success...(this is the output which show at consol after the execution of the program)](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-67-320.jpg)
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Java.io package
The content of a text file testout.txt is set with the data A.
testout.txt
A (this is data which is written by the program in the testout.txt file)
Java FileOutputStream example 2: write string
import java.io.FileOutputStream;
public class FileOutputStreamExample {
public static void main(String args[]){
try{
FileOutputStream fout=new FileOutputStream("D:testout.txt");
String s="Welcome to Aims Tutorial.";
byte b[]=s.getBytes();//converting string into byte array
fout.write(b);
fout.close();
System.out.println("success...");
}catch(Exception e){System.out.println(e);}
}
}
Output:
Success...
The content of a text file testout.txt is set with the data Welcome to Aims Tutorial.
testout.txt
Welcome to Aims Tutorial.
FileInputStream Class
Java FileInputStream class obtains input bytes from a file. It is used for reading byte-oriented
data (streams of raw bytes) such as image data, audio, video etc. You can also read character-
stream data. But, for reading streams of characters, it is recommended to use FileReader
class.
Java FileInputStream class methods
Method Description
int available()
It is used to return the estimated number of bytes that can be read
from the input stream.
int read() It is used to read the byte of data from the input stream.
int read(byte[] b) It is used to read up to b.length bytes of data from the input stream.
int read(byte[] b, int off,
int len)
It is used to read up to len bytes of data from the input stream.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-68-320.jpg)
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Java.io package
long skip(long x)
It is used to skip over and discards x bytes of data from the input
stream.
FileChannel
getChannel()
It is used to return the unique FileChannel object associated with
the file input stream.
FileDescriptor getFD() It is used to return the FileDescriptor object.
protected void finalize()
It is used to ensure that the close method is call when there is no
more reference to the file input stream.
void close() It is used to closes the stream.
Java FileInputStream example 1: read single character
import java.io.FileInputStream;
public class DataStreamExample {
public static void main(String args[]){
try{
FileInputStream fin=new FileInputStream("D:testout.txt");
int i=fin.read();
System.out.print((char)i);
fin.close();
}catch(Exception e){System.out.println(e);}
}
}
Note: Before running the code, a text file named as "testout.txt" is required to be created. In
this file, we are having following content:
Welcome to Aims Tutorial.
After executing the above program, you will get a single character from the file which is 87 (in
byte form). To see the text, you need to convert it into character.
Output:
Welcome to AimsTutorial](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-69-320.jpg)
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Java.io package
Java FileInputStream example 2: read all characters
package com.javatpoint;
import java.io.FileInputStream;
public class DataStreamExample {
public static void main(String args[]){
try{
FileInputStream fin=new FileInputStream("D:testout.txt");
int i=0;
while((i=fin.read())!=-1){
System.out.print((char)i);
}
fin.close();
}catch(Exception e){System.out.println(e);}
}
}
Output:
Welcome to Aims Tutorial
BufferedOutputStream Class
Java BufferedOutputStream class is used for buffering an output stream. It internally uses
buffer to store data. It adds more efficiency than to write data directly into a stream. So, it
makes the performance fast.
For adding the buffer in an OutputStream, use the BufferedOutputStream class. Let's see the
syntax for adding the buffer in an OutputStream:
OutputStream os= new BufferedOutputStream(new FileOutputStream("D:IO Packag
etestout.txt"));
Java BufferedOutputStream class constructors
Constructor Description
BufferedOutputStream(OutputStream os)
It creates the new buffered output stream which is
used for writing the data to the specified output
stream.
BufferedOutputStream(OutputStream os,
int size)
It creates the new buffered output stream which is
used for writing the data to the specified output
stream with a specified buffer size.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-70-320.jpg)
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Java.io package
Java BufferedOutputStream class methods
Method Description
void write(int b) It writes the specified byte to the buffered output stream.
void write(byte[] b, int
off, int len)
It write the bytes from the specified byte-input stream into a
specified byte array, starting with the given offset
void flush() It flushes the buffered output stream.
Example of BufferedOutputStream class:
In this example, we are writing the textual information in the BufferedOutputStream object
which is connected to the FileOutputStream object. The flush() flushes the data of one stream
and send it into another. It is required if you have connected the one stream with another.
package com.javatpoint;
import java.io.*;
public class BufferedOutputStreamExample{
public static void main(String args[])throws Exception{
FileOutputStream fout=new FileOutputStream("D:testout.txt");
BufferedOutputStream bout=new BufferedOutputStream(fout);
String s="Welcome to Aims Tutorial.";
byte b[]=s.getBytes();
bout.write(b);
bout.flush();
bout.close();
fout.close();
System.out.println("success");
}
}
Output:
Success
testout.txt
Welcome to Aims Tutorial.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-71-320.jpg)
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Java.io package
BufferedInputStream Class
Java BufferedInputStream class is used to read information from stream. It internally uses
buffer mechanism to make the performance fast.
The important points about BufferedInputStream are:
When the bytes from the stream are skipped or read, the internal buffer automatically
refilled from the contained input stream, many bytes at a time.
When a BufferedInputStream is created, an internal buffer array is created.
Java BufferedInputStream class constructors
Constructor Description
BufferedInputStream(InputStream IS)
It creates the BufferedInputStream and saves it
argument, the input stream IS, for later use.
BufferedInputStream(InputStream IS,
int size)
It creates the BufferedInputStream with a specified
buffer size and saves it argument, the input stream IS,
for later use.
Java BufferedInputStream class methods
Method Description
int available()
It returns an estimate number of bytes that can be read from the
input stream without blocking by the next invocation method for the
input stream.
int read() It read the next byte of data from the input stream.
int read(byte[] b, int
off, int ln)
It read the bytes from the specified byte-input stream into a specified
byte array, starting with the given offset.
void close()
It closes the input stream and releases any of the system resources
associated with the stream.
void reset()
It repositions the stream at a position the mark method was last
called on this input stream.
void mark(int
readlimit)
It sees the general contract of the mark method for the input stream.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-72-320.jpg)
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Java.io package
long skip(long x) It skips over and discards x bytes of data from the input stream.
boolean
markSupported()
It tests for the input stream to support the mark and reset methods.
Example of Java BufferedInputStream
package com.javatpoint;
import java.io.*;
public class BufferedInputStreamExample
{
public static void main(String args[])
{
try{
FileInputStream fin=new FileInputStream("D:testout.txt");
BufferedInputStream bin=new BufferedInputStream(fin);
int i;
while((i=bin.read())!=-1)
{
System.out.print((char)i);
}
bin.close();
fin.close();
}
catch(Exception e)
{
System.out.println(e);
}
}
}
Here, we are assuming that you have following data in "testout.txt" file:
Aims Tutorial
Output:
Aims Tutorial
BufferedWriter Class
Java BufferedWriter class is used to provide buffering for Writer instances. It makes the
performance fast. It inherits Writer class. The buffering characters are used for providing the
efficient writing of single arrays, characters, and strings.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-73-320.jpg)
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Java.io package
Class constructors
Constructor Description
BufferedWriter(Writer wrt)
It is used to create a buffered character output stream that
uses the default size for an output buffer.
BufferedWriter(Writer wrt,
int size)
It is used to create a buffered character output stream that
uses the specified size for an output buffer.
Class methods
Method Description
void newLine() It is used to add a new line by writing a line separator.
void write(int c) It is used to write a single character.
void write(char[] cbuf, int off, int len) It is used to write a portion of an array of characters.
void write(String s, int off, int len) It is used to write a portion of a string.
void flush() It is used to flushes the input stream.
void close() It is used to closes the input stream
Example of Java BufferedWriter
Let's see the simple example of writing the data to a text file testout.txt using Java
BufferedWriter.
package com.aims;
import java.io.*;
public class BufferedWriterExample {
public static void main(String[] args) throws Exception
{
FileWriter writer = new FileWriter("D:testout.txt");
BufferedWriter buffer = new BufferedWriter(writer);
buffer.write("Welcome to Aims Tutorial.");
buffer.close();
System.out.println("Success");
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-74-320.jpg)
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Java.io package
Output:
success
testout.txt:
Welcome to Aims Tutorial.
BufferedReader Class
Java BufferedReader class is used to read the text from a character-based input stream. It can
be used to read data line by line by readLine() method. It makes the performance fast. It
inherits Reader class.
Java BufferedReader class constructors
Constructor Description
BufferedReader(Reader rd)
It is used to create a buffered character input stream that uses
the default size for an input buffer.
BufferedReader(Reader rd, int
size)
It is used to create a buffered character input stream that uses
the specified size for an input buffer.
Java BufferedReader class methods
Method Description
int read() It is used for reading a single character.
int read(char[] cbuf, int off,
int len)
It is used for reading characters into a portion of an array.
boolean markSupported()
It is used to test the input stream support for the mark and reset
method.
String readLine() It is used for reading a line of text.
boolean ready() It is used to test whether the input stream is ready to be read.
long skip(long n) It is used for skipping the characters.
void reset()
It repositions the stream at a position the mark method was last
called on this input stream.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-75-320.jpg)
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Java.io package
void mark(int
readAheadLimit)
It is used for marking the present position in a stream.
void close()
It closes the input stream and releases any of the system
resources associated with the stream.
Java BufferedReader Example
In this example, we are reading the data from the text file testout.txt using Java
BufferedReader class.
package com.javatpoint;
import java.io.*;
public class BufferedReaderExample
{
public static void main(String args[])throws Exception
{
FileReader fr=new FileReader("D:testout.txt");
BufferedReader br=new BufferedReader(fr);
int i;
while((i=br.read())!=-1)
{
System.out.print((char)i);
}
br.close();
fr.close();
}
}
Here, we are assuming that you have following data in "testout.txt" file:
Welcome to Aims Tutorial.
Output:
Welcome to Aims Tutorial.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-76-320.jpg)
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GUI
public void setVisible(boolean b)
where b==true means visible mode.
where b==false means invisible mode.
Ex: f.setVisible(true);
public void setSize(int width,int height)
Ex: f.setSize(400,500);
3) To provide title to the Frame explicitly we have to use the following method
public void setTitle(String Title)
Ex: f.setTitle("MyFrame");
4) When we create a Frame, the default background color of the Frame is white. If you want to
provide particular color to the Frame we have to use the following method.
public void setBackground(color c)
Ex: f.setBackground(Color.red);
********CREATION OF FRMAE**********
import java.awt.*;
class Demo
{
public static void main(String[] args)
{
//frame creation
Frame f=new Frame();
//set visibility
f.setVisible(true);
//set the size of the frame
f.setSize(400,400);
//set the background
f.setBackground(Color.red);
//set the title of the frame
f.setTitle("Aims Tutorial");
}
};](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-79-320.jpg)
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GUI
Preparation of the components
Label
1) Label is a constant text which is displayed along with a TextField or TextArea.
2) Label is a class which is present in java.awt package.
3) To display the label we have to add that label into the frame for that purpose we have to
use add() method present in the Frame class.
Constructor
Label l=new Label();
Label l=new Label(“user name”);
Ex :-
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("Aims");
f.setBackground(Color.red);
f.setSize(400,500);
Label l=new Label("user name:");
f.add(l);
}
}
TextField
1) TextField is an editable area.
2) In TextField we are able to provide single line of text.
3) Enter Button doesn’t work on TextField. To add TextField into the Frame we have to use
add() method.
1. To set Text to the textarea we have to use the following method.
t.setText(“Aims”);
2. To get the text form the TextArea we have to use fallowing method.
String s=t.getText();
3. To append the text into the TextArea.
t.appendText("Tutorial");](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-80-320.jpg)
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GUI
Constructor:-
TextFiled tx=new TextFiled();
TextField tx=new TextField(“Aims”);
Ex :-
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("Aims");
f.setBackground(Color.red);
f.setSize(400,500);
//TextField tx=new TextField(); empty TextField
TextField tx=new TextField("Manish");
//TextField with data
f.add(tx);
}
}
TextArea
1) TextArea is a class present in java.awt.package.
2) TextArea is a Editable Area. Enter button will work on TextArea.
3) To add the TextArea into the frame we have to use the add()
Construction:-
TextArea t=new TextArea();
TextArea t=new TextArea(int rows,int columns);
4. To set Text to the textarea we have to use the following method.
t.setText(“Aims Tutorial”);
5. To get the text form the TextArea we have to use fallowing method.
String s=t.getText();](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-81-320.jpg)
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GUI
6. To append the text into the TextArea.
t.appendText("Tutorial");
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("AimsTutorial");
f.setBackground(Color.red);
f.setSize(400,500);
f.setLayout(new FlowLayout());
Label l=new Label("user name:");
TextArea tx=new TextArea(4,10);//4 character height 10 character width
tx.appendText("Manish");
tx.setText("Soni");
System.out.println(tx.getText());
f.add(l);
f.add(tx);
}
}
Choice
1) Choice is a class present in java.awt package.
2) List is allows to select multiple items but choice is allow to select single Item.
Constructor:-
Choice ch=new Choice();
Methods :-
1. To add items to the choice we have to use following method.
ch.add(“HYD”);
ch.add(“Chennai”);
ch.add(“BANGALORE”);
2. To remove item from the choice based on the string.
ch.remove(“HYD”);
ch.remove(“BANGALORE”);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-82-320.jpg)
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GUI
3. To remove the item based on the index position
ch.remove(2);
4. To remove the all elements
ch.removeAll();
5. To inset the data into the choice based on the particular position.
ch.insert(2,”ratan”);
6. To get selected item from the choice we have to use following method. String
s=ch.getSelectedItem();
7. To get the selected item index number we have to use fallowing method
int a=ch.getSelectedIndex();
ex:-
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("AimsTutorial");
f.setBackground(Color.red);
f.setSize(400,500);
Choice ch=new Choice();
ch.add("c");
ch.add("cpp");
ch.add("java");
ch.add(".net");
ch.remove(".net");
ch.remove(0);
ch.insert("Manish",0);
f.add(ch);
System.out.println(ch.getItem(0));
System.out.println(ch.getSelectedItem());
System.out.println(ch.getSelectedIndex());
//ch.removeAll();
}
}](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-83-320.jpg)
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GUI
List
1) List is a class it is present in java.awt.package
2) List is providing list of options to select. Based on your requirement we can select any
number of elements. To add the List to the frame we have to use add() method.
CONSTRUCTOR:-
1) List l=new List();
It will creates the list by default size is four elements. And it is allow selecting the only one
item at a time.
2) List l=new List(3);
It will display the three items size and it is allow selecting the only single item.
3) List l=new List(5,true);
It will display the five items and it is allow selecting the multiple items.
Methods:-
1. To add the elements to the List we have to use following method.
l.add(“c”);
l.add(“cpp”);
l.add(“java”);
l.add(“Manish”,0);
2. To remove element from the List we have to use following method.
l.remove(“c”);
l.remove(2);
3. To get selected item from the List we have to use following method.
String x=l.get SelectedItem();
4. To get selected items from the List we have to use following method.
String[] x=s.get SelectedItems()
Ex:-
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("ratan");
f.setBackground(Color.red);
f.setSize(400,500);
f.setLayout(new FlowLayout());
List l=new List(4,true);
l.add("c");](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-84-320.jpg)
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GUI
l.add("cpp");
l.add("java");
l.add(".net");
l.add("ratan");
l.add("arun",0);
l.remove(0);
f.add(l);
System.out.println(l.getSelectedItem());
}
}
Checkbox:-
1) Checkbox is a class present in java.awt package.
2) The user can select more than one checkbox at a time. To add the checkbox to the frame we
have to use add() method.
Constructor:-
1) Checkbox cb1=new CheckBox();
cb1.setLable(“BTECH”);
2) Checkbox cb1=new CheckBox(“MCA”);
3) Checkbox cb3=new CheckBox(“BSC”,true);
Methods:-
1. To set a label to the CheckBox explicitly and to get label from the CheckBox we have to use
the following method.
cb.setLabel(“BSC”);
2. To get the label of the checkbox we have to use fallowing method.
String str=cb.getLabel();
3. To get state of the CheckBox and to set state to the CheckBox we have to use following
method.
Boolean b=ch.getState();
Ex:-
import java.awt.*;
class Test
{
public static void main(String[] args)
{](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-85-320.jpg)
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GUI
Frame f=new Frame();
f.setVisible(true);
f.setTitle("Aims Tutorial");
f.setBackground(Color.red);
f.setSize(400,500);
Checkbox cb1=new Checkbox("BTECH",true);
f.add(cb1);
System.out.println(cb1.getLabel());
System.out.println(cb1.getState());
}
}
RADIO BUTTON:-
1) AWT does not provide any predefined support to create RadioButtons.
2) It is possible to select Only item is selected from group of item. To add the RadioButton to
the frame we have to use add() method.
By using two classes we create Radio Button those are
a)CheckBoxgroup
b)CheckBox
step 1:- Create CheckBox group object.
CheckBoxGroup cg=new CheckBoxGroup();
step 2:- pass Checkbox object to the CheckboxGroup class then the radio buttons are created.
CheckBox cb1=new CheckBox(“male”,cg,false);
CheckBox cb2=new CheckBox(“female”,cg,false);
Methods:-
1) To set status and to get status we have to use setState() and getState() methods.
String str=Cb.getState();
Cb.setState();
2) To get Label and to set Label we have to use following methods.
String str=getLabel()
setLabel(“female”).
Ex:-
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("Aims Tutorial");
f.setBackground(Color.red);
f.setSize(400,500);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-86-320.jpg)
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GUI
CheckboxGroup cg=new CheckboxGroup();
Checkbox cb1=new Checkbox("male",cg,true);
f.add(cb1);
System.out.println(cb1.getLabel());
System.out.println(cb1.getState());
}
}
Layout Managers:-
import java.awt.*;
class Test
{
public static void main(String[] args)
{
Frame f=new Frame();
f.setVisible(true);
f.setTitle("Aims Tutorial");
f.setBackground(Color.red);
f.setSize(400,500);
Label l1=new Label("user name:");
TextField tx1=new TextField();
Label l2=new Label("password:");
TextField tx2=new TextField();
Button b=new Button("login");
f.add(l1);
f.add(tx1);
f.add(l2);
f.add(tx1);
f.add(b);
}
}
Event delegation model:-
1. When we create a component the components visible on the screen but it is not possible to
perform any action for example button.
2. Whenever we create a Frame it can be minimized and maximized and resized but it is not
possible to close the Frame even if we click on Frame close Button.
3. The Frame is a static component so it is not possible to perform actions on the Frame.
4. To make static component into dynamic component we have to add some actions to the
Frame.
5. To attach actions to the Frame component we need event delegation model.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-87-320.jpg)
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GUI
public void windowOpened(WindowEvent e)
{
System.out.println("window Opened");
}
};
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
**PROVIDING CLOSEING OPTION TO THE FRAME***
import java.awt.*;
import java.awt.event.*;
class MyFrame extends Frame
{
MyFrame()
{
this.setVisible(true);
this.setSize(500,500);
this.setBackground(Color.red);
this.setTitle("Aims Tutoiral");
this.addWindowListener(new Listenerimpl());
}
};
class Listenerimpl extends WindowAdapter
{
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
};
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-91-320.jpg)
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GUI
Note ;- by using WindowAdaptor class we can close the frame. Internally WindowAdaptor
class implements WindowListener interface. Hence WindowAdaptor class contains empty
implementation of abstract methods.
****PROVIDING CLOSEING OPTION THE FRAME******
import java.awt.*;
import java.awt.event.*;
class MyFrame extends Frame
{
MyFrame()
{
this.setVisible(true);
this.setSize(500,500);
this.setBackground(Color.red);
this.setTitle("trialAims T");
this.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
});
}
}
class FrameEx
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
***WRITE SOME TEXT INTO THE FRAME********
import java.awt.*;
class MyFrame extends Frame
{
MyFrame()
{
this.setVisible(true);
this.setSize(500,500);
this.setBackground(Color.red);
this.setTitle("rattaiah");
}
public void paint(Graphics g)
{
Font f=new Font("arial",Font.BOLD,20);
g.setFont(f);
this.setForeground(Color.green);
g.drawString("HI BTECH ",100,100);
g.drawString("good boys &",200,200);
g.drawString("good girls",300,300);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-92-320.jpg)
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GUI
}
}
class FrameEx
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
------------------------------------------------
********LAYOUT MACHANISUMS FLOWLAYOUT**********
import java.awt.*;
import java.awt.event.*;
class MyFrame extends Frame
{
Label l1,l2;
TextField tx1,tx2;
Button b;
MyFrame()
{
this.setVisible(true);
this.setSize(340,500);
this.setBackground(Color.green);
this.setTitle("Aims Tutorial");
l1=new Label("user name:");
l2=new Label("password:");
tx1=new TextField(25);
tx2=new TextField(25);
b=new Button("login");
tx2.setEchoChar('*');
this.setLayout(new FlowLayout());
this.add(l1);
this.add(tx1);
this.add(l2);
this.add(tx2);
this.add(b);
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-93-320.jpg)
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GUI
----------------------------------------------------
*****BORDERLAYOUT**********
import java.awt.*;
class MyFrame extends Frame
{
Button b1,b2,b3,b4,b5;
MyFrame()
{
this.setBackground(Color.green);
this.setSize(400,400);
this.setVisible(true);
this.setLayout(new BorderLayout());
b1=new Button("Boys");
b2=new Button("Girls");
b3=new Button("management");
b4=new Button("Teaching Staff");
b5=new Button("non-teaching staff");
this.add("North",b1);
this.add("Center",b2);
this.add("South",b3);
this.add("East",b4);
this.add("West",b5);
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
---------------------------------------------------
********CardLayout*************
import java.awt.*;
class MyFrame extends Frame
{
MyFrame()
{
this.setSize(400,400);
this.setVisible(true);
this.setLayout(new CardLayout());
Button b1=new Button("button1");
Button b2=new Button("button2");
Button b3=new Button("button3");
Button b4=new Button("button4");
Button b5=new Button("button5");
this.add("First Card",b1);
this.add("Second Card",b2);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-94-320.jpg)
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GUI
this.add("Thrid Card",b3);
this.add("Fourth Card",b4);
this.add("Fifth Card",b5);
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
********GRIDLAYOUT**********
import java.awt.*;
class MyFrame extends Frame
{
MyFrame()
{
this.setVisible(true);
this.setSize(500,500);
this.setTitle("rattaiah");
this.setBackground(Color.red);
this.setLayout(new GridLayout(4,4));
for (int i=0;i<10 ;i++ )
{ Button b=new Button(""+i);
this.add(b);
}
};
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
*********ACTIONLISTENER**********
import java.awt.*;
import java.awt.event.*;
class myframe extends Frame implements ActionListener
{
TextField tx1,tx2,tx3;
Label l1,l2,l3;
Button b1,b2;
int result;
myframe()
{
this.setSize(250,400);
this.setVisible(true);
this.setLayout(new FlowLayout());](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-95-320.jpg)
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GUI
l1=new Label("first value");
l2=new Label("second value");
l3=new Label("result");
tx1=new TextField(25);
tx2=new TextField(25);
tx3=new TextField(25);
b1=new Button("add");
b2=new Button("mul");
b1.addActionListener(this);
b2.addActionListener(this);
this.add(l1);
this.add(tx1);
this.add(l2);
this.add(tx2);
this.add(l3);
this.add(tx3);
this.add(b1);
this.add(b2);
}
public void actionPerformed(ActionEvent e)
{
try{
int fval=Integer.parseInt(tx1.getText());
int sval=Integer.parseInt(tx2.getText());
String label=e.getActionCommand();
if (label.equals("add"))
{
result=fval+sval;
}
if (label.equals("mul"))
{
result=fval*sval;
}
tx3.setText(""+result);
}
catch(Exception ee)
{
ee.printStackTrace();
}
}
};
class Demo
{
public static void main(String[] args)
{
myframe f=new myframe();
}
};](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-96-320.jpg)
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GUI
this.setForeground(Color.green);
g.drawString("Status:----"+status,50,300);
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
------------------------------------------------------------------------------------------------------------------------
----------------
******MENUITEMS************
import java.awt.*;
import java.awt.event.*;
class MyFrame extends Frame implements ActionListener
{
String label="";
MenuBar mb;
Menu m1,m2,m3;
MenuItem mi1,mi2,mi3;
MyFrame()
{
this.setSize(300,300);
this.setVisible(true);
this.setTitle("myFrame");
this.setBackground(Color.green);
mb=new MenuBar();
this.setMenuBar(mb);
m1=new Menu("new");
m2=new Menu("option");
m3=new Menu("edit");
mb.add(m1);
mb.add(m2);
mb.add(m3);
mi1=new MenuItem("open");
mi2=new MenuItem("save");
mi3=new MenuItem("saveas");
mi1.addActionListener(this);
mi2.addActionListener(this);
mi3.addActionListener(this);
m1.add(mi1);
m1.add(mi2);
m1.add(mi3);
}
public void actionPerformed(ActionEvent ae)
{
label=ae.getActionCommand();](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-98-320.jpg)
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GUI
repaint();
}
public void paint(Graphics g)
{
Font f=new Font("arial",Font.BOLD,25);
g.setFont(f);
g.drawString("Selected item....."+label,50,200);
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
------------------------------------------------------------------------------------------------------------------------
----------------
*****MOUSELISTENER INTERFACE**********
import java.awt.*;
import java.awt.event.*;
class myframe extends Frame implements MouseListener
{
String[] msg=new String[5];
myframe()
{
this.setSize(500,500);
this.setVisible(true);
this.addMouseListener(this);
}
public void mouseClicked(MouseEvent e)
{
msg[0]="mouse clicked......("+e.getX()+","+e.getY()+")";
repaint();
}
public void mousePressed(MouseEvent e)
{
msg[1]="mouse pressed......("+e.getX()+","+e.getY()+")";
repaint();
}
public void mouseReleased(MouseEvent e)
{
msg[2]="mouse released......("+e.getX()+","+e.getY()+")";
repaint();
}
public void mouseEntered(MouseEvent e)
{
msg[3]="mouse entered......("+e.getX()+","+e.getY()+")";
repaint();](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-99-320.jpg)
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GUI
}
public void mouseExited(MouseEvent e)
{
msg[4]="mouse exited......("+e.getX()+","+e.getY()+")";
repaint();
}
public void paint(Graphics g)
{
int X=50;
int Y=100;
for(int i=0;i<msg.length;i++)
{
if (msg[i]!=null)
{
g.drawString(msg[i],X,Y);
Y=Y+50;
}
}
}
};
class Demo
{
public static void main(String[] args)
{
myframe f=new myframe();
}
};
------------------------------------------------------------------------------------------------------------------------
----------------
*******ITEMLISTENER INTERFACE**********
import java.awt.*;
import java.awt.event.*;
class myframe extends Frame implements ItemListener
{
String qual="",gen="";
Label l1,l2;
CheckboxGroup cg;
Checkbox c1,c2,c3,c4,c5;
Font f;
myframe()
{
this.setSize(300,400);
this.setVisible(true);
this.setLayout(new FlowLayout());
l1=new Label("Qualification: ");
l2=new Label("Gender: ");
c1=new Checkbox("BSC");
c2=new Checkbox("BTECH");
c3=new Checkbox("MCA");](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-100-320.jpg)
![Aims Tutorial
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GUI
}
}
class rc
{
public static void main(String[] args)
{
myframe f=new myframe();
}
};
------------------------------------------------------------------------------------------------------------------------
----------------
*********KEYLISTENER INTERFACE***********
import java.awt.*;
import java.awt.event.*;
class myframe extends Frame
{
myframe()
{
this.setSize(400,400);
this.setVisible(true);
this.setBackground(Color.green);
this.addKeyListener(new keyboardimpl());
}
};
class keyboardimpl implements KeyListener
{
public void keyTyped(KeyEvent e)
{
System.out.println("key typed "+e.getKeyChar());
}
public void keyPressed(KeyEvent e)
{
System.out.println("key pressed "+e.getKeyChar());
}
public void keyReleased(KeyEvent e)
{
System.out.println("key released "+e.getKeyChar());
}
}
class Demo
{
public static void main(String[] args)
{
myframe f=new myframe();
}
};](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-102-320.jpg)
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GUI
---------------------------------------------------------------------------------------------------------------------------------------
***********CHECK LIST AND CHOICE************
import java.awt.*;
import java.awt.event.*;
class myframe extends Frame implements ItemListener
{
Label l1,l2;
List l;
Choice ch;
String[] tech;
String city="";
myframe()
{
this.setSize(300,400);
this.setVisible(true);
this.setLayout(new FlowLayout());
l1=new Label("Technologies: ");
l2=new Label("City: ");
l=new List(3,true);
l.add("c");
l.add("c++");
l.add("java");
l.addItemListener(this);
ch=new Choice();
ch.add("hyd");
ch.add("chenni");
ch.add("Banglore");
ch.addItemListener(this);
this.add(l1);
this.add(l);
this.add(l2);
this.add(ch);
}
public void itemStateChanged(ItemEvent ie)
{
tech=l.getSelectedItems();
city=ch.getSelectedItem();
repaint();
}
public void paint(Graphics g)
{
Font f=new Font("arial",Font.BOLD,20);
g.setFont(f);
String utech="";
for(int i=0;i<tech.length ;i++ )
{
utech=utech+tech[i]+" ";
}
g.drawString("tech:-------"+utech,50,200);
g.drawString("city---------"+city,50,300);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-103-320.jpg)
![Aims Tutorial
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GUI
utech="";
}
}
class Demo
{
public static void main(String[] args)
{
myframe f=new myframe();
}
};
-----------------------------------------------
*********AdjustmentListener**********
import java.awt.*;
import java.awt.event.*;
class myframe extends Frame implements AdjustmentListener
{
Scrollbar sb;
int position;
myframe()
{
this.setSize(400,400);
this.setVisible(true);
this.setLayout(new BorderLayout());
sb=new Scrollbar(Scrollbar.VERTICAL);
this.add("East",sb);
sb.addAdjustmentListener(this);
}
public void adjustmentValueChanged(AdjustmentEvent e)
{
position=sb.getValue();
}
public void paint(Graphics g)
{
g.drawString("position:"+position,100,200);
repaint();
}
}
class scrollbarex
{
public static void main(String[] args)
{
myframe f=new myframe();
}
};](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-104-320.jpg)
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GUI
SWINGS
1. Sun Micro Systems introduced AWT to prepare GUI applications.
2. awt components not satisfy the client requirement.
3. An alternative to AWT Netscape Communication has provided set of GUI components in the form of
IFC(Internet Foundation Class).
4. IFC also provide less performance and it is not satisfy the client requirement.
5. In the above contest[sun+Netscape] combine and introduced common product to design GUI
applications.
Differences between awt and Swings:
1. AWT components are heavyweight component but swing components are light weight component.
2. AWT components consume more number of system resources Swings consume less number of system
resources.
3. AWT components are platform dependent but Swings are platform independent.
4. AWT is provided less number of components where as swings provides more number of components.
5. AWT doesn’t provide Tooltip Test support but swing components have provided Tooltip test support.
6. in awt for only window closing : windowListener
windowAdaptor
In case of swing use small piece of code.
i. f.setDefaultCloseOption(JFrame.EXIT-ON-CLOSE);
7. AWT will not follow MVC but swing follows MVC Model View Controller It is a design pattern to provide
clear separation b/w controller part,model part,view part.
a. Controller is a normal java class it will provide controlling.
b. View part provides presentation
c. Model part provides required logic.](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-105-320.jpg)
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GUI
ButtonGroup bg=new ButtonGroup();
bg.add(rb1);
bg.add(rb2);
String[] listitems={"cpp","c","java"};
l=new JList(listitems);
String[] cbitems={"hyd","pune","bangalore"};
cb=new JComboBox(cbitems);
ta=new JTextArea(5,20);
b=new JButton("submit");
c.add(l1);
c.add(tf);
c.add(l2);
c.add(pf);
c.add(l3);
c.add(cb1);
c.add(cb2);
c.add(cb3);
c.add(l4);
c.add(rb1);
c.add(rb2);
c.add(l5);
c.add(l);
c.add(l6);
c.add(cb);
c.add(l7);
c.add(ta);
c.add(b);
}
}
class SwingDemo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
----------------------------------------------------------------------------------------------------------------------------------------
********JCOLORCHOOSER***********
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
class MyFrame extends JFrame implements ChangeListener
{
JColorChooser cc;
Container c;
MyFrame()
{
this.setVisible(true);
this.setSize(500,500);
this.setTitle("SWING GUI COMPONENTS EXAMPLE");](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-107-320.jpg)
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GUI
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
c=getContentPane();
cc=new JColorChooser();
cc.getSelectionModel().addChangeListener(this);
c.add(cc);
}
public void stateChanged(ChangeEvent c)
{
Color color=cc.getColor();
JFrame f=new JFrame();
f.setSize(400,400);
f.setVisible(true);
f.getContentPane().setBackground(color);
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
********JFILECHOOSER*********************
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
class MyFrame extends JFrame implements ActionListener
{
JFileChooser fc;
Container c;
JLabel l;
JTextField tf;
JButton b;
MyFrame()
{
this.setVisible(true);
this.setSize(500,500);
this.setTitle("SWING GUI COMPONENTS EXAMPLE");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
c=getContentPane();
l=new JLabel("Select File:");
tf=new JTextField(25);
b=new JButton("BROWSE");
this.setLayout(new FlowLayout());
b.addActionListener(this);
c.add(l);
c.add(tf);
c.add(b);](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-108-320.jpg)
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GUI
}
public void actionPerformed(ActionEvent ae)
{
class FileChooserDemo extends JFrame implements ActionListener
{
FileChooserDemo()
{
Container c=getContentPane();
this.setVisible(true);
this.setSize(500,500);
fc=new JFileChooser();
fc.addActionListener(this);
fc.setLayout(new FlowLayout());
c.add(fc);
}
public void actionPerformed(ActionEvent ae)
{
File f=fc.getSelectedFile();
String path=f.getAbsolutePath();
tf.setText(path);
this.setVisible(false);
}
}
new FileChooserDemo();
}
}
class Demo
{
public static void main(String[] args)
{
MyFrame f=new MyFrame();
}
};
-----------------------------------------
********JTABLE******************
import javax.swing.*;
import java.awt.*;
import javax.swing.table.*;
class Demo1
{
public static void main(String[] args)
{
JFrame f=new JFrame();
f.setVisible(true);
f.setSize(300,300);
Container c=f.getContentPane();
String[] header={"ENO","ENAME","ESAL"};
Object[][] body={{"111","aaa",5000},{"222","bbb",6000},{"333","ccc",7000},{"444","ddd",8000}};
JTable t=new JTable(body,header);
JTableHeader th=t.getTableHeader();
c.setLayout(new BorderLayout());](https://image.slidesharecdn.com/javanotes-170519183618/85/Java-notes-109-320.jpg)
Java notes
- 1. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 1 By: Manish Swarnkar 9887474850 Java Training Module c (A Software Development Company and Training Center) Contact Information: Contact No: +91-8947920041, 9829761399 Email: [email protected] [email protected] Website: www.aimstutorial.com www.integrationedutech.com Address Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020
- 2. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 2 By: Manish Swarnkar 9887474850 Java Java is an object oriented programming language originally developed by Sun Micro System and released in 1995. Java was originally by James Gosling at Sun Microsystems (which has since merge in Oracle Corporation). Java programs are platform independent which means they can be run on any operating system. Java codes that run on one platform does not need to recompile to run on another platform, it’s called “write once run anywhere”. Java Features 1. Object Oriented Java is an object oriented programming language which follows the concepts of oop’s. 2. Platform Independent Java application programs written on one operating system can be able to run on any platform. So the java is platform independent. On compilation java program is compiled into byte code (.class file). This byte code is platform independent and can be run on any machine, in addition to this bytecode format also provide security. Any machine with Java Runtime Environment can run java programs. 3. Simple Java syntax is similar to c and c++ and it follow the oop’s concepts so it is easy to learn.
- 3. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 3 By: Manish Swarnkar 9887474850 4. Secure Java’s securing feature it enable to develop virus free, tamper free (software which is not modify by attacker). Authentication techniques are based on public key encryption Note: A cryptographic system that uses two keys -- a public key known to everyone and a private or secret key known only to the recipient of the message. When John wants to send a secure message to Jane, he uses Jane's public key to encrypt the message. Jane then uses her private key to decrypt it. Class loader- It adds security by separation by separating the package for the classes of the local file system from those that are imported from network sources. Byte code verifiers-It checks the code fragments for illegal code that can violate access right to objects. Security Manager- It determines what resources a class can access such as reading and writing to the local disk. High Performance- Compilation of program to an architecture independent machine like language, result in a small efficient interpreter of java programs. The java environment also complies the java byte code into native machine code at runtime. 5. Architectural Neutral Java compiler generates an architectural neutral object file format which makes the compiler code to be executed on many processors, with the presence of java runtime system. In C programming, int data type occupies 2 bytes of memory for 32-bit architecture and 4 bytes of memory for 64-bit architecture. But in java, it occupies 4 bytes of memory for both 32 and 64 bit architectures. 6. Portable We may carry the java byte code to any platform. 7. Robust Robust simply means strong. Java uses strong memory management. There is lack of pointers that avoids security problem. There is automatic garbage collection in java. There is exception handling and type checking mechanism in java. All these points make java robust. 8. Multi Threaded A thread is like a separate program, executing concurrently. We can write Java programs that deal with many tasks at once by defining multiple threads. The main advantage of multi-threading is that it doesn't occupy memory for each thread. It shares a common memory area. Threads are important for multi-media, Web applications etc. 9. Interpreted Java is a compiled programming language, but rather than compile straight to executable machine code, it compiles to an intermediate binary form called JVM byte code. The byte code is then compiled and/or interpreted to run the program. 10. High Performance Java is faster than traditional interpretation since byte code is "close" to native code still somewhat slower than a compiled language (e.g., C++)
- 4. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 4 By: Manish Swarnkar 9887474850 11. Distributed We can create distributed applications in java. RMI and EJB are used for creating distributed applications. We may access files by calling the methods from any machine on the internet. 12. Dynamic Java is considered more dynamic than c and c++. In java the application can be create more dynamic. Types of java Application 1. Web Application Java is used to create server side applications. Currently , servelet, jsp, struts, jsf etc technology are used. 2. Stand- Alone Application It is also known as desktop application or window based application. An application that we need to install on every machine such as antivirus, media player etc. AWT and Swing is used in java for creating standalone application. 3. Enterprise Application An application that is distributed in nature, such as banking application etc. In java EJB is used to create enterprise application. 4. Mobile application Java is used to create application software for mobile devices. Currently java ME is used for creating application for small devices and java is programming for Google Android application development. Different Editions of java Technology 1. Java SE Java SE or Java Standard Edition provides tools and API’s that can use to create server application, desktop application and even applets. These programs developed using java SE can be run on almost every popular operating system include Linux, Macintosh, Solaris, and Windows. 2. JEE Based on the foundation framework of the standard edition, java Enterprise Edition helps in web application service, component model and enterprise class service oriented architecture. 3. JME Java Micro Edition or JME is use for the development of software for devices like mobile phones, PDA’s, TV set-top box, game programming.
- 5. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 5 By: Manish Swarnkar 9887474850 C++ v/s Java Comparison C++ Java Platform- independent C++ is platform-dependent. Java is platform-independent. Mainly used for C++ is mainly used for system programming. Java is mainly used for application programming. It is widely used in window, web-based, enterprise and mobile applications. Goto C++ supports goto statement. Java doesn't support goto statement. Multiple inheritance C++ supports multiple inheritance. Java doesn't support multiple inheritance through class. It can be achieved by interfaces in java. Operator Overloading C++ supports operator overloading. Java doesn't support operator overloading. Pointers C++ supports pointers. You can write pointer program in C++. you can't write the pointer program in java. It means java has restricted pointer support in java. Compiler and Interpreter C++ uses compiler only. Java uses compiler and interpreter both. Call by Value and Call by reference C++ supports both call by value and call by reference. Java supports call by value only. There is no call by reference in java. Structure and Union C++ supports structures and unions. Java doesn't support structures and unions. Thread Support C++ doesn't have built-in support for threads. It relies on third-party libraries for thread support. Java has built-in thread support. Documentation comment C++ doesn't support documentation comment. Java supports documentation comment (/** ... */) to create documentation for java source code. Virtual Keyword C++ supports virtual keyword so that we can decide whether or not override a function. Java has no virtual keyword. We can override all non-static methods by default. In other words, non-static methods are virtual by default. unsigned right shift >>> C++ doesn't support >>> operator. Java supports unsigned right shift >>> operator that fills zero at the top for the negative numbers. For positive numbers, it works same like >> operator. Inheritance Tree C++ creates a new inheritance tree always. Java uses single inheritance tree always because all classes are the child of Object class in java. Object class is the root of inheritance tree in java.
- 6. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 6 By: Manish Swarnkar 9887474850 Java oop’s Concepts or java oop’s paradigm Object Oriented Programming is a paradigm that provides many concepts such as inheritance, data binding, polymorphism etc. The programming paradigm where everything is represented as an object is known as truly object-oriented programming language. OOPs (Object Oriented Programming System) Object means a real word entity such as pen, chair, table etc. Object-Oriented Programming is a methodology or paradigm to design a program using classes and objects. It simplifies the software development and maintenance by providing some concepts: Object Class Inheritance Abstraction Encapsulation Polymorphism Class It is similar to structures in C language. Class can also be defined as user defined data type but it also contains functions in it. So, class is basically a blueprint for object. A class enclosed both the data and function that operate on the data, into a single unit. The variable and function enclosed in a class are called member and member functions respectively. Member functions define the permission operation on the data member of a class. data Data 1 Data2 Data3 fun()1 fun()2 fun(3) function
- 7. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 7 By: Manish Swarnkar 9887474850 Object Objects are the basic unit of OOP. They are instances of class, which have data members and use various member functions to perform tasks. Object is the basic unit of object-oriented programming. Objects are identified by its unique name. An object represents a particular instance of a class. There can be more than one instance of a class. Each instance of a class can hold its own relevant data. Inheritance Inheritance is the process of forming a new class from an existing class or base class. The base class is also known as parent class or super class. The new class that is formed is called derived class. Derived class is also known as a child class or sub class. Inheritance helps in reducing the overall code size of the program, which is an important concept in object-oriented programming. Inheritance is a way to reuse once written code again and again. The derived class can use all the functions which are defined in base class, hence making code reusable. Animal Mammal Reptile Elephant Tiger Crocodile Data1 Data2 Fun1 Fun2 Data Function Obj 2 Obj 1 Data function Data function Obj 3 Data function
- 8. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 8 By: Manish Swarnkar 9887474850 Data Abstraction Abstraction refers to showing only the essential features of the application and hiding the details. In C++, classes provide methods to the outside world to access & use the data variables, but the variables are hidden from direct access. Data abstraction allows a program to ignore the details of how a data type is represented. Abstraction (derived from a Latin word , meaning away from and , meaning to draw) refers to the act of representing essential features without including the background details or explanations. While classifying a class, both data members and member functions are expressed in the code. But, while using an object (that is an instance of a class) the built in data types and the members in the class get ignored which is known as data abstraction. Data Encapsulation Data encapsulation is a mechanism of bundling the data, and the functions that use them and data abstraction is a mechanism of exposing only the interfaces and hiding the implementation details from the user. It can also be said data binding. Encapsulation is all about binding the data variables and functions together in class. C++ supports the properties of encapsulation and data hiding through the creation of user-defined types, called classes. We already have studied that a class can contain private, protected and public members. By default, all items defined in a class are private. Polymorphism The term Polymorphism get derived from the Greek word where ‘poly’+ ‘morphos’ where ‘poly’ means many and ‘morphos’ means forms. Polymorphism makes the code more readable. It is a feature, which lets is create functions with same name but different. The word polymorphism means having many forms. Typically, polymorphism occurs when there is a hierarchy of classes and they are related by inheritance. Shap Draw() Box obj Draw(Box) Triangle obj Draw(Triangle) Circle obj Draw(Circle)
- 9. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 9 By: Manish Swarnkar 9887474850 Setting Path for Java Java is freely available on the oracle website Download the latest version of JDK(java Development Kit)on your machine. Install JDK on your machine. Once you have installed java on your machine it need to set environment variable to point to correct installation directory. An environment variable is a dynamic “object ” on a computer that stores a value (like a key value ), which can be reference by one or more software programs in Windows. Like in java , we will set environment variable with name ”java” and its values will be the path of /bin directory present variable which will give it the path to the execution. Step: 1 Right click on My Computer icon and select properties. Step: 2 Go to Advance Setting Tab
- 10. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 10 By: Manish Swarnkar 9887474850 Step: 3 Click on Environment Variable Button Step:4 Now alter the path variable so that it also contains the path to jdk installed directory.
- 11. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 11 By: Manish Swarnkar 9887474850 First java Program public class FirstJava { public static void main(String[] args) { System.out.println("Welcome in Aims"); } } class: class is a keyword is used to declare classes in java public: It is an access specifiers . Public means this function is visible to all. static: static is used to make a function static. To execute a static function you do not have to create an Object of the class. The main () method here is called by jvm, without creating any object for class. void: void is return type, meaning this function will not return anything. main(): main() method is the most important method in a java program . this is the method which is executed hence all logic must be inside the main() method. If a java class is not having a main() method, it causes compilation error. System.out.println(): This is used to print anything on the consol like printf()in c. Steps to compile and Run FirstJava Program Step: 1 Open a text editor like Notepad and write the code as above. Step: 2 save the file as FirstJava.java Step: 3Open command prompt and go to the directory where you saved your first java program
- 12. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 12 By: Manish Swarnkar 9887474850 Step: 4 Type javac FirstJava.java then enter to compile the program Step: 5 Now Type java FirstJava on command prompt the enter to run program. Step: 6 Now you will be able to see Welcome in Aims oriented on your command prompt.
- 13. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 13 By: Manish Swarnkar 9887474850 Java Development Kit (JDK) JDK is an acronym for Java Development Kit. It physically exists. It contains JRE + the complete set of class file for all the java technology package, which include basic language classes.GUI components classes, an advanced collection API, and so no. Java Virtual Machine (JVM) It is an abstract machine or imaginary machine that is implemented by emulating it in software on a real machine. Code for JVM is stored in .class file. It is a specification that provides runtime environment in which java bytecode can be executed. JVMs are available for many hardware and software platforms. JVM, JRE and JDK are platform dependent because configuration of each OS differs. But, Java is platform independent. The JVM specification provides concrete definition for the implementation of the following: an instruction set (equivalent to that of a center processing machine [CPU]), a register set, the class file format, a runtime stack, a garbage-collector heap a memory area etc. The JVM performs following main tasks: Loads code Verifies code Executes code Provides runtime environment JVM Internal Architecture It contains 1. Class loader: class loader loads all classes needed for the execution of a program. The class loader adds security. 2. Memory area 1. Class (Method) Area: Class (Method) Area stores per-class structures such as the runtime constant pool, field and method data, the code for methods. 2. Heap: It is the runtime data area in which objects are allocated. 3. Stack: It holds local variables and partial results, and plays a part in method invocation and return. 4. Program counter Registers: PC (program counter) register. It contains the address of the Java virtual machine instruction currently being executed. 5. Native Method Stack: It contains all the native methods used in the application. 3. Execution engine It contains 1. A virtual processor 2. Interpreter: Read byte code stream the execute the instruction
- 14. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 14 By: Manish Swarnkar 9887474850 Java Runtime Environment (JRE) It is used to provide runtime environment. It is the implementation of JVM. It physically exists. It contains set of libraries + other files that JVM uses at runtime. Implementation of JVMs is also actively released by other companies besides Sun Micro Systems.
- 15. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 15 By: Manish Swarnkar 9887474850 Difference between JRE and JDK Sr. no JRE JDK 1 JRE is an implementation of the java Virtual Machine which actually executes java program JDk is bundle of software that is used to develop java base application 2 Java Runtime Environment is a plug- in needed for running java programs Java Development Kit is needed for developing java application 3 JRE include the JVM, core libraries And other additional component to run application and applets written in java JDk include the JRE, set of API classes, java complier and additional files needed to write java applets and applications. Byte Code: When the java program compile the source code is converted in intermediate code with extension .class called, Byte Code which is read by the JVM machine. Byte code and JVM both makes java platform independent. Just-In-Time (JIT) Compiler In some Java technology runtime environments a portion of verified byte code is compiled to native machine code by the JIT(Just-In-Time compiler)and execute directly on the hardware platform. This compiler is called Just-IN-Time Complier. It enables the java software code to run close to the speed of C or C++ with small delay at load time to enable the code to be compiled to the native machine code.
- 16. Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Introduction of java Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 16 By: Manish Swarnkar 9887474850 Byte Code Verifier Java software code passes several tasks before running on your machine. The JVM puts the code through byte code verifiers that tests the format of code fragments and check code for illegal code, called byte code verifiers. It provides securities for java programs. Garbage Collection It provides a system-level thread that tracks each memory allocation. During idle cycles in the JVM, the garbage collection threads checks for and free any memory that can freed. Garbage collection happens automatically during the life time of a java technology program, eliminating the need to deal locate memory and avoiding memory leak.
- 17. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 17 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens Tokens Each and every smallest individual unit in a program is known as tokens. Tokens are the basic buildings blocks in language which are constructed together to write a program. The keywords, identifiers, constants, string literals, and operators are examples of tokens. Punctuation characters such as brackets [ ], braces { }, parentheses ( ), and commas (,) are also tokens. 1.Keywords Keywords are those words whose meaning is already defined by language There are 50 Keywords in java. Keywords are also called as reserved words. const and goto are two keywords which are reserved in java but not defined by java language. abstract continue goto package switch assert default if private this boolean do implements protected throw break double import public throws byte else instanceof return transient case extern int short try catch final interface static void char finally long stricfp volatile class float native super while const for new synchronized
- 18. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 18 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens 2.Identifiers Identifiers are the name given to various programming element like variable name, class name, object name array name, function name interface name, package name. Rules for constructing identifier name All the identifiers must start with either a letter (a to z or A to z) or currency character ($) or an underscore. They can have alphabets, digits, and the underscore (_) and dollar sign ($) characters. They must not begin with a digit. After first character, an identifier can have any combination of character. A java keyword cannot use as an identifiers. Identifiers in java are case sensitive abc and ABC are two different identifiers. Uppercase and lowercase are distinct. Java developers have followed some naming conventions. 1. When more than one word are used in a public methods and instance name, the second and subsequent words are marked with a leading letters. Examples: dayTemperature firstDayOfMonth totalMarks 2. All private and local variable use only lowercase letters combine with underscores. Examples: length batch_strength 3. All classes and interface start with uppercase letter(and each subsequent word with a leading uppercase) Example: Student HelloJava Vehical MotorCycle 4. Variables that represent constant values use all uppercase letter and underscore between words. Example: TOTAL F_MAX PRINCIPAL_AMOUNT 5. Package name should be in lowercase Example: java, lang, sql, util, etc. 6. Method name should be in lowercase letters. Example: print (), println().
- 19. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 19 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens 3.Constants or Literals Constants or Literals are the fixes values which are not change during the execution of the programs. Literals are a sequence of characters (digits, letters, and other characters) that represent constant values to be stored in a variable. Constants or Literals are declare using final keywords There are five major types of literals. 1. Integer literals Integers are any numeric values either positive or negative without having fractional part. Integer datatype consists of the following primitive data types: byte, int, short, long can be expressed in decimal(base 10), hexadecimal(base 16) or octal(base 8) number system. Example: final int decimal=100; final int octal=0144; final int hexa=0x64; 2. Floating literals Floats are the numeric values either negative or positive having fractional parts. Java has two types of floating point numbers: float and double. By default floating point literals is double We can define the floating point literals by appending F or f suffix after the values. Example: final float pi=3.14f; 3. Character literals A Character literals is a single character in a pair of single quote such as ‘a’, ‘#’ Char datatypes is a single 16-bit Unicode character. Example: final char ch=’A’; final char ch=’u0041’; final char ch=’t’; final char ch=’u0009’; Escape Sequence Characters Escape Character Meaning n New line t Tab b Backspace r Carriage return f Form feed backslash ’ single quote ”” double quotation marks
- 20. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 20 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens 4. String literals The set of characters represented as String literals. It is use “double quotes”. final String ch="Aims"; 5. Boolean literals The values true and false are treated as literals in java. When we assign a value to a boolean variable is true or false. final boolean bool=true; 4.Operator Operator is the special symbols the perform the mathematical and logical manipulation. Types of operator 1. Arithmetic operator Operators which are used for arithmetical operation (+, -, *, /, and %) called arithmetic operator. Operator Meaning + Addition - Subtraction * Multiplication / Division % Modulus 2. Relational operator Operators are used to test the relation between two values called relational operator. All relational operators are binary operators and therefore require two operands. A relational expression returns false when the relation is false and a true when it is true. Relational Operators Meaning < Less than <= Less than or equal to == Equal to > Greater than >= Greater than or equal to ! = Not equal to public class RelationalOperatorsDemo { public static void main(String args[]) { int x = 10, y = 5; System.out.println("x > y : "+(x > y)); System.out.println("x < y : "+(x < y)); System.out.println("x >= y : "+(x >= y)); System.out.println("x <= y : "+(x <= y)); System.out.println("x == y : "+(x == y)); System.out.println("x != y : "+(x != y)); } }
- 21. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 21 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens 3. Logical operator Operators which are used to combine one or more relational expression called logical operator. Operators Meaning operation || OR a||b is true && AND a&&b is false ! NOT (!a) is false public class LogicalOperatorsDemo { public static void main(String args[]) { boolean x = true; boolean y = false; System.out.println("x & y : " + (x & y)); System.out.println("x && y : " + (x && y)); System.out.println("x | y : " + (x | y)); System.out.println("x || y: " + (x || y)); System.out.println("x ^ y : " + (x ^ y)); System.out.println("!x : " + (!x)); } } 4. Bitwise operator These operators are used to perform bit operations. Decimal values are converted into binary values which are the sequence of bits and bit wise operators work on these bits. Bit wise operators in java are & (bitwise AND), | (bitwise OR), ~ (bitwise OR), ^ (XOR), << (left shift) and >> (right shift). Operator Meaning & Bitwise AND | Bitwise OR ^ Bitwise XOR ~ One ‘Complement >> Bitwise right shift << Bitwise left Shift Truth Table of Bitwise operator x y x|y x&y x^y 0 0 0 0 0 0 1 1 0 1 1 0 1 0 1 1 1 1 1 0
- 22. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 22 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens public class BitwiseOperatorsDemo { public static void main(String args[]) { int x = 0xFAEF; //1 1 1 1 1 0 1 0 1 1 1 0 1 1 1 1 int y = 0xF8E9; //1 1 1 1 1 0 0 0 1 1 1 0 1 0 0 1 int z; System.out.println("x & y : " + (x & y)); System.out.println("x | y : " + (x | y)); System.out.println("x ^ y : " + (x ^ y)); System.out.println("~x : " + (~x)); System.out.println("x << y : " + (x << y)); System.out.println("x >> y : " + (x >> y)); System.out.println("x >>> y : " + (x >>> y)); } } 5. Ternary operator Operator that performs operation on three operands called ternary operator. Conditional Operator The conditional operator ? : is called ternary operator as it requires three operands. Syntax: Conditional Exp? Exp1: Exp2 If the value of conditional expression is true then the exp1 is evaluated, otherwise exp2 is evaluated. public class TernaryOperatorsDemo { public static void main(String args[]) { int x = 10, y = 12, z = 0; z = x > y ? x : y; System.out.println("z : " + z); } } 6. Assignment operator Operator ('=') which is used for assigning a value to a variable is called assignment operator. This operator takes the expression on its right-hand-side and places it into the variable on its left-hand-side. For example: m = 5; Operator Example Equivalent to + = A + = 2 A = A + 2 - = A - = 2 A = A - 2 % = A % = 2 A = A % 2 /= A/ = 2 A = A / 2 *= A * = 2 A = A * 2
- 23. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 23 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens 7. Increment or decrement operator Operator which perform operation only on one operand are called Unary operator. 1. Increment Operator ++ Operator increment the value of a variable by 1 is called increment operator. Pre-increment ++ is written before variable name. Value is incremented first then incremented value is used in expression. Ex: public class IncPre { public static void main(String args[]) { int i, a=5; i=++a; System.out.println(i); } }OUTPUT: 6 Post-increment ++ is written after variable name. Value is assigned to expression after that the value is increment. Ex: public class IncPre { public static void main(String args[]) { int i, a=5; i=a++; System.out.println(i); } }OUTPUT:5 2. Decrement Operator -- Operator decrement the value of a variable by 1 is called decrement operator. Pre-decrement -- is written before variable name. Value is decremented first then decremented value is used in expression. Ex: public class IncPre { public static void main(String args[]) { int i, a=5; i=--a; System.out.println(i); } }OUTPUT: 4
- 24. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 24 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Tokens Post-decrement -- is written after variable name. Value is assigned in expression then the decrement the value. Ex: public class IncPre { public static void main(String args[]) { int i, a=5; i=a--; System.out.println(i); } }OUTPUT:5 5.Separator The separators define the structure of a program. The separators are used parentheses ( ), braces { }, the period (.) and (;) semicolon. Comments Comments are special part of the program, to describe or explain the code which make easy to understand. Comments are those lines which are not read by the compilers. Types of Comments 1. Single line comments Single line comments starts with two forward slash (//) It useful when only single lines are commented. final int a=5// a is constants variable 2. Multiline comments Multiline comments are starts with forward slash/ and after that star (*) and the text or comment line put then again star(*) put the again forward slash(/) put to comment . It is useful when we comment multiple line in program. 3. Document comment /** document comment*/ This is document comment it described the author and other information about a program. The JDK javadoc tool uses doc comment for automatically generated documentation.
- 25. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 25 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Data Types Data Types: Data type are the keyword which assign a type to a variable. There are two data types available in Java Primitive Data Types Reference/Object Data Types Primitive Data Types Eight Primitive datatypes are predefined by the java. byte Byte data type is an 8-bit signed two's complement integer Minimum value is -128 (-2^7) Maximum value is 127 (inclusive)(2^7 -1) Default value is 0 Byte data type is used to save space in large arrays, mainly in place of integers, since a byte is four times smaller than an integer. Example: byte a = 100, byte b = -50 short Short data type is a 16-bit signed two's complement integer Minimum value is -32,768 (-2^15) Maximum value is 32,767 (inclusive) (2^15 -1) Short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer Default value is 0. Example: short s = 10000, short r = -20000 int Int data type is a 32-bit signed two's complement integer. Minimum value is - 2,147,483,648 (-2^31) Maximum value is 2,147,483,647(inclusive) (2^31 -1) Integer is generally used as the default data type for integral values unless there is a concern about memory. The default value is 0 Example: int a = 100000, int b = -200000 long Long data type is a 64-bit signed two's complement integer Minimum value is -9,223,372,036,854,775,808(-2^63) Maximum value is 9,223,372,036,854,775,807 (inclusive)(2^63 -1) This type is used when a wider range than int is needed Default value is 0L Example: long a = 100000L, long b = -200000L
- 26. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 26 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Data Types float Float data type is a single-precision 32-bit IEEE 754 floating point Float is mainly used to save memory in large arrays of floating point numbers Default value is 0.0f Float data type is never used for precise values such as currency Example: float f1 = 234.5f double double data type is a double-precision 64-bit IEEE 754 floating point This data type is generally used as the default data type for decimal values, generally the default choice Double data type should never be used for precise values such as currency Default value is 0.0d Example: double d1 = 123.4 boolean boolean data type represents one bit of information There are only two possible values: true and false This data type is used for simple flags that track true/false conditions Default value is false Example: boolean one = true char char data type is a single 16-bit Unicode character Minimum value is 'u0000' (or 0) Maximum value is 'uffff' (or 65,535 inclusive) Char data type is used to store any character Example: char letterA = 'A' Reference Datatypes Reference variables are created using defined constructors of the classes. They are used to access objects. These variables are declared to be of a specific type that cannot be changed. For example, Employee, Puppy, etc. Class objects and various type of array variables come under reference datatype. Default value of any reference variable is null. A reference variable can be used to refer any object of the declared type or any compatible type. Example: Animal animal = new Animal("giraffe");
- 27. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 27 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Class Class “Class is a user defined data types, which holds variables and , which can be accessed and used by creating instance of that class.” Class is just a blue print, which declare and defined variables and methods. All objects of this class will share these data member and function. About Class: 1. Class name start with an uppercase letter. If class name is made then one word, the first letter of each word must be in uppercase. Ex:- Class Study, class AimsTutorial 2. Objects of the class holds separate copies of data member. We can create as many objects of a class as we need. How to declare class: Syntax: public class Class_Name { variables; methods( ); public static void main(String[] args) { Class_Name obj=new Class_Name() } }; Example: public class Aims { int i=10; public static void main(String[] args) { Aims a1=new Aims(); System.out.println(a1.i); } } Output: 10; Objects Objects are the variable which declare using class name, it holds the data variable, declared in the class and the member function works on these class objects. How to declare objects: public class Abc { int x=10; void display( ) { System.out.println(x); }
- 28. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 28 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Class public static void main(String[] args) { Abc obj=new Abc(); Obj.display(); } } Output:10 Each object has different data variables. Object are initialized using special methods are called constructor. A class can contain any of the following variable types. Local variables − Variables which defined inside methods, constructors or blocks are called local variables. The variable will be declared and initialized within the method and the variable will be destroyed when the method has completed. class Test { public static void main(String[] args) { int a=10; Local variables int b=20; System.out.println(a+b); } } Instance variables − Instance variables are variables within a class but outside any method. These variables are initialized when the class is instantiated. Instance variables can be accessed from inside any method, constructor or blocks of that particular class. class Test { int a=10; int b=20; void add() { System.out.println(a+b); } public static void main(String[] args) { Test t=new Test(); System.out.println(t.a+t.b); t.add(); } }
- 29. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 29 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Array Static variable or Class variables − Class variables are variables declared within a class, outside any method, with the static keyword. class Test { static int b=20; public static void main(String[] args) { System.out.println(b);//20 } } Arrays:- 1) Array is a final class inheritance is not possible. 2) Arrays are used to store the multiple numbers of elements of single type. 3) The length of the array is established at the time of array creation. After creation the length is fixed. Root structure:- java.lang.Object +--java.lang.reflect.Array public final class Array extends Object single dimensional array declaration:- int[] a; int []a; int a[]; declaration & instantiation & initialization :- approach 1:- int a[]={10,20,30,40}; approach 2:- int[] a=new int[100]; a[0]=10; a[1]=20; a[2]=30; a[4]=40; 10 20 30 40 50 60 70 80 90 Ex:-printing the array elements class Test { public static void main(String[] args) { int[] a={10,20,30,40}; System.out.println(a[0]); System.out.println(a[1]); System.out.println(a[2]); System.out.println(a[3]); } }
- 30. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 30 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Array Ex:-printing the array elements by using for loop class Test { public static void main(String[] args) { int[] a={10,20,30,40}; for (int i=0;i<a.length;i++) { System.out.println(a[i]); } } } declaration of two dimensional array:- int[][] a; int [][]a; int a[][]; int []a[]; Ex:- class Test { public static void main(String[] args) { int[][] a={{10,20,30},{40,50,60}}; System.out.println(a[0][0]);//10 System.out.println(a[1][0]);//40 System.out.println(a[1][1]);//50 } } Methods (behaviors):- 1) Methods are used to provide the business logic of the project. 2) The methods like a functions in C-language called functions, in java language is called methods. 3) Inside the class it is possible to declare any number of methods based on the developer requirement. 4) As a software developer while writing method we have to fallow the coding standards like the method name starts with lower case letters if the method contains two words every inner word also starts uppercase letter. 5) It will improve the reusability of the code. By using methods we can optimize the code. Syntax:- [modifiers-list] return-Type Method-name (parameter-list)throws Exception Ex:- public void m1() public void m2(int a, int b) Method Signature:- The name of the method and parameter list is called Method Signature. Return type and modifiers list not part of a method signature. Ex:- m1(int a,int b)------Method Signature m2();------------------Method signature
- 31. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 31 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Array There are two types of methods:- Instance method Method which are declare and defined inside a class and without static keyword and called using object. class Test { void display() { System.out.println("Aims Tutorial"); } public static void main(String[] args) { Test t=new Test(); t.display(); } } Static method Method which are declare and defined inside a class and with static keyword and called using classname. class Test { Static void display() { System.out.println("Aims Tutorial"); } public static void main(String[] args) { Test.display(); } }
- 32. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 32 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Constructor Heap memory Stack memory 1) It is used to store the objects 1) It is used to store the function calls and local variables. 2) We are getting outOfMemoryError 2) If the there is no memory in the stack to store method calls or local variables the JVM will throw the StackOverflowError. 3) Having more memory compared with the stack memory. 4) Heap memory is also known as public memory. This is applicable all the objects. This memory is shared by all threads. 5)the objects are created in the heap memory with the help of new operator 3) Stack memory is very less memory when compared with the heap memory 4) Stack memory also known as private memory. This is applicable only for owners. 5) Destroy when the method is completed. Jvm is creating stack memory Constructor Constructor is a special type of method which has same as class that is used to initialize the object. Constructor is called at the time of object creation. It constructs the value or provides data for the object that is why it is known as constructor. Rules for creating constructor 1. Constructor name must be same as its class name. 2. Constructor must have no return type. Types of constructor 1. Default constructor. A Constructor that have no parameter is known as default constructor. Purpose of default constructor Default constructor provide the default value to the object 0,null etc depending on the type. class Bike { public static void main(String args[]) { Bike b=new Bike(); } Bike() { System.out.println(“Default constructor is created”); } }
- 33. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 33 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Constructor 2. Parameterized constructor. A Constructor that has parameter is known as parameterized constructor. Why use parameterized Constructor parameterized constructor provide the different values to the distinct object class Square { public static void main(String args[]) { Square b=new Square (5); } Square(int n) { System.out.println(n*n); } } this heyword:- This keyword is used to represent 1. Current class variables. 2. Current class methods. 3. Current class constructors. class Test { int a=10; int b=20; void add(int a,int b) { System.out.println(a+b); System.out.println(this.a+this.b); } public static void main(String[] args) { Test t=new Test(); t.add(100,200); } }
- 34. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 34 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Inheritance INHERITANCE Inheritance is the capability of acquire property(variables) and behaviors(methods) of another class is called inheritance. 1. The main purpose of the inheritance is code extensibility whenever we are extending automatically the code is reused. 2. In inheritance one class giving the properties and behavior and another class is taking the properties and behavior. 3. Inheritance is also known as is-a relationship means two classes are belongs to the same hierarchy. 4. By using extends keyword we are achieving inheritance concept. 5. In the inheritance the person who is giving the properties is called parent the person who is taking the properties is called child. 6. To reduce length of the code and redundancy of the code sun peoples introducing inheritance concept. Types of Inheritance 1. Single Inheritance In this inheritance one derived class inherits from only one base class. It is the simplest form of inheritance. A Base class B Derived class
- 35. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 35 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Inheritance 2. Multiple Inheritance In this type of inheritance a single derived class inherits from two or more than two base classes. 3. Multilevel Inheritance In this type of inheritance the derived class inherits from a class, which is turn inherits from some other class. The super class for one is sub class for another class. A Base class B Base class C Derived class B Derived class A Base class C Derived class
- 36. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 36 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Inheritance 4. Hierarchical Inheritance In this type of inheritance multiple derived classes are inherits from a single base class. 5. Hybrid Inheritance Hybrid inheritance is combination of multiple and multilevel inheritance. Two or more type of inheritance are used to design called Hybrid inheritance. A Derived class B Derived class C Base class B Derived class C Derived class A Base class D Derived class
- 37. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 37 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Inheritance 1. Single Inheritance public class Shap { int width; int height; void setdata(int w, int h) { width=w; height=h; } } class Rectangle extends Shap { int getArea() { return(width*height); } public static void main(String[] args) { Rectangle Rect; Rect.setdata(5,7); System.out.prinln(“Total Area="+Rect.getArea()); } 2. Multilevel publc class Student { int rollno; void read(int rollno) { this.rollno=rollno; } }
- 38. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 38 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Inheritance class Marks extends Student { int m1, m2, m3; void getMarks(int m1,int m2,int m3) { this.m1=m1; this.m2=m2; this.m3=m3; } } class Result extends Marks { int total; void process() { total=m1+m2+m3; } void print() { System.out.prinln(“Total result="+total); } public static void main(String[] args) { Result R; R.read(); R.getMarks(); R.process(); R.print(); } } Output: Enter RollNo=234 Enter Marks in Sub1=20 Enter Marks in Sub2=30 Enter Marks in Sub3=40 Total result=90
- 39. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 39 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Inheritance 3. Hierarchal public class Shap { int width; int height; void setdata(int w, int h) { width=w; height=h; } } public class Rectangle extends Shap { int getArea() { return width*height; } } public class Triangle extends Shap { int getArea() { return (width*height)/2; } public static void main(String[] args) { Rectangle rect; Triangle tri; rect.setdata(5,7); tri.setdata(5,8); System.out.println(“Area of Rectangle="+rect.getArea()); System.out.prinln(“Area of Triangle="+tri.getArea()); } }
- 40. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 40 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Polymorphism POLYMORPHISM 1) One thing can exhibits more than one form called polymorphism. 2) The ability to appear in more forms. 3) Polymorphism is a Greek word poly means many and morphism means forms. Types of Polymorphism 1. Compile Time Polymorphism (Early binding, Static binding) 2. Run Time Polymorphism (Late binding, Dynamic binding) Ex:-Method Overloading Ex:-Method Overriding A. Method overloading ( Compile Time Polymorphism ,Early binding, Static binding) If any class has multiple method with same name but different parameters then they are said to be overloaded. Function overloading allows to use the same name for different function to performed either same or different action in the same class. Method overloading is usually used to enhance the readability of the program. If you have to perform one single operation but with different number or types of arguments, then you can simply overload the method There are two types of method overloading in java 1. By Changing number of arguments Class Cal { void add(int a, int b) { System.out.prinln(a+b); } void add(int a, int b, int c) { System.out.prinln(a+b+c); } public static void main(String args[]) { Cal C1=new Cal(); C1.add(2,4); C1.add(2,3,4); } } 2. By having different types of arguments Class Cal { void add(int a, int b) { System.out.prinln(a+b); } void add(float a, float b)
- 41. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 41 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Polymorphism { System.out.prinln(a+b); } public static void main(String args[]) { Cal C1=new Cal(); C1.add(2,4); C1.add(2.5f,3.4f); } } B. Constructor overloading Just like Method constructor can be overloaded. We can define multiple constructors with different parameters to overload. Class Cal { void Cal(int a, int b) { System.out.prinln(a+b); } void Cal(int a, int b, int c) { System.out.prinln(a+b+c); } public static void main(String args[]) { Cal C1=new Cal(2,3); Cal C2=new Cal(3,4,5); } } B. Method Overriding If we inherit a class into the derived class and provide a definition for one of the base class’s method again. The method is said to be overriding. Requirement for method overriding Inheritance should be there. method overriding cannot be done within a class, for this we require a derived class and a base class. method signature should be same in base class and derived class. class Base { void show() { System.out.prinln(“Base Class”+”t"); } }
- 42. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 42 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Polymorphism class Derived extends Base { void show() { System.out.prinln("Derived Class"); } public static void main(String[]args) { Base B=new Base(); Derived D=new Derived(); B.show(); D.show(); } } Output: Base Class Derived Class In the above example, we are calling the overridden function using Base Class and Derived Class object. Base class object call base class version of function and derived class’s object call Derived class version of function. Difference between method overloading and method overriding in java There are many differences between method overloading and method overriding in java. A list of differences between method overloading and method overriding are given below: No. Method Overloading Method Overriding 1) Method overloading is used to increase the readability of the program. Method overriding is used to provide the specific implementation of the method that is already provided by its super class. 2) Method overloading is performed within class. Method overriding occurs in two classes that have IS-A (inheritance) relationship. 3) In case of method overloading, parameter must be different. In case of method overriding, parameter must be same. 4) Method overloading is the example of compile time polymorphism. Method overriding is the example of run time polymorphism. 5) In java, method overloading can't be performed by changing return type of the method only. Return type can be same or different in method overloading. But you must have to change the parameter. Return type must be same or covariant in method overriding.
- 43. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 43 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Abstraction ABSTRACTION Hiding the internal implementation details and highlighting the essential functionality to the user this mechanism is called abstraction. Ex: a. Bank ATM Screens (Hiding thee internal implementation and highlighting set of services like withdraw, money transfer, mobile registration). b. Mobile phones (The mobile persons are hiding the internal circuit implementation and highlighting touch screen). Abstraction concepts are implemented in java by abstract class and interface 1. Abstract Class Abstract class is a java class which contains at least one abstract method. To specify the particular class is abstract and particular method is abstract method by using abstract modifier. For the abstract classes it is not possible to create an object. Because it contains the unimplemented methods. For any class if we don’t want instantiation then we have to declare that class as abstract i.e., for abstract classes instantiation (creation of object) is not possible. abstract class Test { abstract void m3(); } Abstract class:- class Test { abstract void m1(); abstract void m2(); abstract void m3(); } abstract class Add { abstract void add(int a, int b); } class Cal extends Add { void add(int a, int b) { System.out.println(a+b); } public static void main(String[] args) { Cal C1=new Cal(); C1.add(3,4); } }
- 44. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 44 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Abstraction Abstract methods:- The method which is having declaration but not implementations such type of methods are called abstract Method. Hence every abstract method should end with “;”. The child classes are responsible to provide implementation for parent class abstract methods. public abstract Add { abstract void add(int a, int b);//it is abstract method which has no definition } class Cal { void add(int a, int b) { System.out.println(a+b); } public static void main(String[] args) { Cal C1=new Cal(); C1.add(3,4); } } 2. Interface 1. Interface is also one of the type of class it contains only abstract methods. 2. For the interfaces also .class files will be generated. 3. Each and every interface by default abstract hence it is not possible to create an object. 4. Interfaces not alternative for abstract class it is extension for abstract classes. 5. 100 % pure abstract class is called interface. 6. The Interface contains only abstract methods means unimplemented methods. 7. Interfaces giving the information about the functionalities it are not giving the information about internal implementation. 8. To provide implementation for abstract methods we have to take separate class that class we can called it as implementation class for that interface. 9. Interface can be implemented by using implements keyword. 10. For the interfaces also the inheritance concept is applicable. Syntax:- Interface interface-name Ex:- interface it1 Note: - if we are declaring or not By default interface methods are public abstract interface it1 abstract interface it1 { { Void m1(); Both are same public abstract void m1(); Void m2(); public abstract void m2(); } }
- 45. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 45 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Abstraction interface Cal { void add(int a, int b); void sub(int a, int b); } class Solution implements Cal { void add(int a, int b) { System.out.prinln(a+b); } void sub(int a, int b) { System.out.prinln(a-b); } public static void main(String[] args) { Solution S1=new Solution()’ S1.add(); S1.sub(); } } Adaptor class:- It is a intermefdiate class between the interface and user defined class. And it contains empty implementation of interface methods. Limitation of interface advantage of adaptor classes interface it { void m1(); void m2(); ; ; void m100() } Class Test implements it { Must provide implementation of 100 methods otherwise compiler raise compilation error } interface it { void m1(); void m2(); ; ; void m100() ; }
- 46. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 46 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Abstraction class Adaptor implements it { void m1() { } void m2() { } ; ; void m100() { } }; class Test implements it { must provide the 100 methods implementation }; class Test extends Adaptor { provide the implementation of required methods. };
- 47. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 47 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Encapsulation Encapsulation The process of binding the data and code as a single unit is called encapsulation. We are able to provide more encapsulations by taking the private data(variables) members. To get and set the values from private members use getters and setters to set the data and to get the data. Ex:- class Encapsulation { private int sid; private int sname; public void setSid(int x) { this.sid=sid; } public int getSid() { return sid; } public void setSname(String sname) { this.sname=sname; } public String getSname() { return sname; } } To access encapsulated use fallowing code:- class Test { public static void main(String[] args) { Encapsulation e=new Encapsulation(); e.setSid(100); e.setSname("ratan"); int num=e.getSid(); String name=e.getSname(); System.out.println(num); System.out.println(name); } }
- 48. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 48 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Super key-word Super Key-word Super:- Super keyword is used to represent 1) Call the Super class variable. 2) Call the super class constructor. 3) Call the super class methods. Super keyword is not required class Parent { int a=10; int b=20; } class Child extends Parent { int x=100; int y=200; void add(int i,int j) { System.out.println(i+j); System.out.println(x+y); System.out.println(a+b); } public static void main(String[] args) { Child c=new Child(); c.add(1000,2000); } } Super keyword is required class Test1 { int a=10; int b=20; }; class Test extends Test1 { int a=100; int b=200; void add(int a,int b) { System.out.println(a+b); System.out.println(this.a+this.b); System.out.println(super.a+super.b); }
- 49. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 49 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Super key-word public static void main(String[] args) { Test t=new Test(); t.add(1000,2000); } } Command Line Arguments:- The arguments which are passed from command prompt is called command line arguments. We are passing command line arguments at the time program execution. Ex1:- class Test { public static void main(String[] args) { System.out.println(args.length); System.out.println(args[0]); System.out.println(args[1]); } } Compilation : Javac Test.java Execution : java Test a b c //a,b,c are the command line arguments Output : 3 a b Modifiers Modifiers are the keyword which define the accessibility or scope of a variable , class method in the program. 1. Public This is the modifier applicable for classes, methods and variables (only for instance and static variables but not for local variables). If a class is declared with public modifier then we can access that class from anywhere (within the package and outside of the package). If we declare a member(variable) as a public then we can access that member from anywhere but Corresponding class should be visible i.e., before checking member visibility we have to check class visibility. Ex:- public class Test // public class can access anywhere { public int a=10; //public variable can access any where public void m1() //public method can access any where { System.out.println("public method access in any package"); }
- 50. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 50 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Modifiers public static void main(String[] args) { Test t=new Test(); t.m1(); System.out.println(t.a); } } 2. Default:- This is the modifier applicable for classes, methods and variables (only for instance and static variables but not for local variables). If a class is declared with <default> modifier then we can access that class only within that current package but not from outside of the package. Default access also known as a package level access. The default modifier in the java language is default. class Test { void m1() { System.out.println("m1-method"); } void m2() { System.out.println("m2-method"); } public static void main(String[] args) { Test t=new Test(); t.m1(); t.m2(); } } in the above program we are not providing any modifier for the methods and classes at that situation the default modifier is available for methods and classes that is default modifier. Hence we can access that methods and class with in the package. 3. Private:- Private is a modifier applicable for methods and variables. If a member declared as private then we can access that member only from within the current class. If a method declare as a private we can access that method only within the class. it is not possible to call even in the child classes also. class Test { private void m1() { System.out.println("we can access this method only with in this class"); }
- 51. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 51 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Modifiers public static void main(String[] args) { Test t=new Test(); t.m1(); } } 4. Protected :- If a member declared as protected then we can access that member with in the current package anywhere but outside package only in child classes. But from outside package we can access protected members only by using child reference. If we try to use parent reference we will get compile time error. Members can be accesses only from instance area directly i.e., from static area we can’t access instance members directly otherwise we will get compile time error. Ex:-demonstrate the user defined packages and imports. Aims project source file:- package calculator; public class Cal { protected void add(int a, int b) { System.out.println(a+b); } protected void sub(int a, int b) { System.out.println(a-b); } protected void multi(int a, int b) { System.out.println(a*b); } } import calculator.Cal; public class Solution extends Cal { public static void main(String[] args) { Solution S1=new Solution(); S1.add(3,4); S1.sub(3,2); S1.multi(3,5); } }
- 52. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 52 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String String 1) String is a final class it is present in java.lang package. 2) String is nothing but a group of characters or character array. 3) Once we are creating String object it is not possible to do the modifications on existing object called immutability nature. Constructors of string class:- 1) String str=new String(java.lang.String); This constructor takes the String as a argument. Ex:- String str=new String(“Aims”); System.out.println(str);//Aims 2) Stirng str=new String(char[]); This constructor take the array of characters as a argument. Ex:- char[] ch={'a','b','c','d'}; String str1=new String(ch); System.out.println(str1); //abcd 3) String str=new String(char[] ,int ,int ); This contractor takes the array of characters with starting index and ending index. First int represent the starting position Second int represent the ending position. Ex:- char[] ch={'a','b','c','d'}; String str1=new String(ch,1,3); System.out.println(str1);//bcd Ex:- class Test { public static void main(String[] args) { String str="Manish"; System.out.println(str); //Manish String str1=new String("Manish"); System.out.println(str1); //Manish String str2=new String(str1); System.out.println(str2); char[] ch={'a','i','m','s'}; String str3=new String(ch); System.out.println(str3); //aims char[] ch1={'t','u','t','o','r','i','a',’l’}; String str4=new String(ch1,1,5); System.out.println(str4); //utorial } }
- 53. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 53 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String String is immutability nature:- Once we are creating string object it is not possible to do the modifications on the existing object is called immutability nature. public class Test { public static void main(String[] args) { String str1=new String("Aims"); str1.concat("Tutorial”); System.out.println(str1); } } OUTPUT: Aims String class Methods Method Description 1 char charAt(int index) returns char value for the particular index 2 int length() returns string length 3 String concat(String str) concatenates specified string 4 int indexOf(int ch) returns specified char value index 5 String toLowerCase() returns string in lowercase. 6 String toUpperCase() returns string in uppercase. 7 String trim() removes beginning and ending spaces of this string. 8 static String valueOf(int value) converts given type into string. It is overloaded. String charAt() The java string charAt() method returns a char value at the given index number. The index number starts from 0 public class CharAtExample { public static void main(String args[]) { String name="AimsTutorial"; char ch=name.charAt(4); //returns the char value at the 4th index System.out.println(ch);
- 54. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 54 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String } } String length() The java string length() method length of the string. It returns count of total number of characters. The length of java string is same as the unicode units of the string. public class LengthExample { public static void main(String args[]) { String s1="java"; String s2="python"; System.out.println("string length is: "+s1.length()); //10 is the length of javatpoint string System.out.println("string length is: "+s2.length()); //6 is the length of python string } } String concat() The java string concat() method combines specified string at the end of this string. It returns combined string. It is like appending another string. public class ConcatExample { public static void main(String args[]) { String s1="java string"; s1.concat("is immutable"); System.out.println(s1); s1=s1.concat(" is immutable so assign it explicitly"); System.out.println(s1); } } String indexOf() The java string indexOf() method returns index of given character value or substring. If it is not found, it returns -1. The index counter starts from zero. public class IndexOfExample { public static void main(String args[]) { int index4=s1.indexOf('s');//returns the index of s char value System.out.println(index4);//3 } }
- 55. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 55 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String String toLowerCase() The java string toLowerCase() method returns the string in lowercase letter. In other words, it converts all characters of the string into lower case letter. public class StringLowerExample { public static void main(String args[]) { String s1="AMIS TUTORIAL"; String s1lower=s1.toLowerCase(); System.out.println(s1lower); } } String toUpperCase The java string toUpperCase() method returns the string in uppercase letter. In other words, it converts all characters of the string into upper case letter. public class StringUpperExample { public static void main(String args[]) { String s1="hello string"; String s1upper=s1.toUpperCase(); System.out.println(s1upper); } } String trim The java string trim() method eliminates leading and trailing spaces. The unicode value of space character is 'u0020'. The trim() method in java string checks this unicode value before and after the string, if it exists then removes the spaces and returns the omitted string. public class StringTrimExample { public static void main(String args[]) { String s1=" hello student "; System.out.println(s1+"welcome");//without trim() System.out.println(s1.trim()+"in aims");//with trim() } }
- 56. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 56 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String StringBuffer 1. String Buffer is a class present in the java.lang package. 2. StringBuffer is a final class so it can’t be inherited. 3. StringBuffer is a mutable class so it is possible to change the content in the same location. 4. StringBuffer .equals() method is used for reference comparison. What is mutable string A string that can be modified or changed is known as mutable string. StringBuffer and StringBuilder classes are used for creating mutable string. Constructors:- 1. StringBuffer sb=new StringBuffer(); 2. StringBuffer sb1=new StringBuffer(int capacity); 3. StringBuffer sb2=new StringBuffer(String str); 1) StringBuffer append() method The append() method concatenates the given argument with this string. class A { public static void main(String args[]) { StringBuffer sb=new StringBuffer("Hello "); sb.append("Java");//now original string is changed System.out.println(sb);//prints Hello Java } } 2) StringBuffer insert() method The insert() method inserts the given string with this string at the given position. class A { public static void main(String args[]) { StringBuffer sb=new StringBuffer("Hello "); sb.insert(1,"Java");//now original string is changed System.out.println(sb);//prints HJavaello } }
- 57. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 57 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String 3) StringBuffer replace() method The replace() method replaces the given string from the specified beginIndex and endIndex. class A { public static void main(String args[]) { StringBuffer sb=new StringBuffer("Hello"); sb.replace(1,3,"Java"); System.out.println(sb);//prints HJavalo } } 4) StringBuffer delete() method The delete() method of StringBuffer class deletes the string from the specified beginIndex to endIndex. class A { public static void main(String args[]) { StringBuffer sb=new StringBuffer("Hello"); sb.delete(1,3); System.out.println(sb);//prints Hlo } } 5) StringBuffer reverse() method The reverse() method of StringBuilder class reverses the current string. class A { public static void main(String args[]) { StringBuffer sb=new StringBuffer("Hello"); sb.reverse(); System.out.println(sb);//prints olleH } }
- 58. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 58 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String 6) StringBuffer capacity() method The capacity() method of StringBuffer class returns the current capacity of the buffer. The default capacity of the buffer is 16. If the number of character increases from its current capacity, it increases the capacity by (oldcapacity*2)+2. For example if your current capacity is 16, it will be (16*2)+2=34. class A { public static void main(String args[]) { StringBuffer sb=new StringBuffer(); System.out.println(sb.capacity());//default 16 sb.append("Hello"); System.out.println(sb.capacity());//now 16 sb.append("java is my favourite language"); System.out.println(sb.capacity());//now (16*2)+2=34 i.e (oldcapacity*2)+2 } } Java StringBuilder class Java StringBuilder class is used to create mutable (modifiable) string. The Java StringBuilder class is same as StringBuffer class except that it is non-synchronized. It is available since JDK 1.5. Important Constructors of StringBuilder class 1. StringBuilder(): creates an empty string Builder with the initial capacity of 16. 2. StringBuilder(String str): creates a string Builder with the specified string. 3. StringBuilder(int length): creates an empty string Builder with the specified capacity as length. Difference between String and StringBuffer There are many differences between String and StringBuffer. A list of differences between String and StringBuffer are given below: No. String StringBuffer 1) String class is immutable. StringBuffer class is mutable. 2) String is slow and consumes more memory when you concat too many strings because every time it creates new StringBuffer is fast and consumes less memory when you cancat
- 59. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 59 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] String instance. strings. 3) String class overrides the equals() method of Object class. So you can compare the contents of two strings by equals() method. StringBuffer class doesn't override the equals() method of Object class. Difference between StringBuffer and StringBuilder There are many differences between StringBuffer and StringBuilder. A list of differences between StringBuffer and StringBuilder are given below: No. StringBuffer StringBuilder 1) StringBuffer is synchronized i.e. thread safe. It means two threads can't call the methods of StringBuffer simultaneously. StringBuilder is non-synchronized i.e. not thread safe. It means two threads can call the methods of StringBuilder simultaneously. 2) StringBuffer is less efficient than StringBuilder. StringBuilder is more efficient than StringBuffer. Java toString() method If you want to represent any object as a string, toString() method comes into existence. The toString() method returns the string representation of the object. If you print any object, java compiler internally invokes the toString() method on the object. So overriding the toString() method, returns the desired output, it can be the state of an object etc. depends on your implementation. class Student { int rollno; String name; String city; Student(int rollno, String name, String city) { this.rollno=rollno; this.name=name; this.city=city; } public static void main(String args[]) { Student s1=new Student(101,"Raj","lucknow"); Student s2=new Student(102,"Vijay","ghaziabad"); System.out.println(s1.toString); System.out.println(s2);//compiler writes here s2.toString() } }
- 60. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 60 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Wrapper Classes Wrapper classes 1) To represent primitive data types as a Object form we required some classes these classes are called wrapper classes. 2) All wrapper classes present in the java.lang package. 3) Int,byte…. Acts as a primitives we can make the primitives into the objects is called wrapper calless the the wrapper classes are Integer,Short-----. 4) We are having 8 primitive data types hence sun peoples are providing 8 wrapper classes. Data types and corresponding wrapper classes:- byte ----- Byte short ----- Short int ----- Integer long ----- Long float ----- Float double ----- Double boolean ----- Boolean char ------ Character 6) Byte,Short,Integer,Long,Float,Double these are child classes of Number class. Constructors of wrapper classes:- All most all wrapper classes contain two constructors:- 1. Integer i=new Integer(10); 2. Integer i=new Integer(“10”); Primitives Wrapper classes Fallowing constructor arguments byte short int long float double char Boolean Byte Short Integer Long Float Double Character Boolean Byte or String Short or String Int or String Long or String Float or double or String double or String Char Boolean or String
- 61. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 61 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Wrapper Classes Wrapper classes hierarchy The main importance of wrapper classes:- 1. To convert a data types into the object means we are giving object from data types by using constructor. 2. To convert String into the data types by using parsexxx() method Utility methods:- 1. valueOf() 2. xxxValue() 3. parsexxx() 1) valueOf():- By using valueof() we are creating wrapper object and it is a alternative to the constructor. class Test { public static void main(String[] args) { //by using constructor converting String/primitive to wrapper object Integer i=new Integer(10); System.out.println(i); //by using valueOf() converting String/primitive to the wrapper object Boolean b=Boolean.valueOf("true"); System.out.println(b); } }
- 62. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 62 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Wrapper Classes XxxValue():- by using XXXValue() method we are converting wrapper objects into the corresponding primitive values class Test { public static void main(String[] args) { Integer i=Integer.valueOf(150); System.out.println("byte value :"+i.byteValue());//-106 System.out.println("short value :"+i.shortValue());//150 System.out.println("int value :"+i.intValue());//150 System.out.println("long value :"+i.longValue());//150 System.out.println("float value :"+i.floatValue());//150.0 System.out.println("double value :"+i.doubleValue());//150.0 Character c=new Character('s'); char ch=c.charValue(); System.out.println(ch); Boolean b=new Boolean(false); boolean bb=b.booleanValue(); System.out.println(bb); } } parseXXX():- by using above method we are converting String into the corresponding primitive. class Test { public static void main(String[] args) { String str1="10"; String str2="20"; System.out.println(str1+str2);//1020 int a=Integer.parseInt(str1); float f=Float.parseFloat(str2); System.out.println(a+f);//30.0 } } Autoboxing and Autounboxing:-(introduced in the 1.5 version) Until 1.4 version we are not allowed to place primitive in the wrapper and wrapper in the place of primitive. The programmer is responsible person to do the explicit conversion primitive to the wrapper and wrapper to the primitive. Autoboxing:- Integer i=10; System.out.println(i); The above statement does not work on the 1.4 and below versions. The auto conversion of the primitive into the Wrapper object is called the autoboxing these conversions done by compiler at the time of compilation.
- 63. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 63 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Wrapper Classes Autounboxing:- int a=new Integer(100); System.out.println(a); The auto conversion of the wrapper object to the primitive value is called autounboxing and these conversions are done by compiler at the time of compilation. Ex :- class Test { static Integer i=10;//i is wrapper object static int j;//j is primitive variable static void print(int i) { j=i; System.out.println(j); } public static void main(String[] args) { print(i); System.out.println(j); } } Automatic conversion of the primitive to wrapper and wrapper to the primitive:-
- 64. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 64 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package Java.io package Java io(input/output) is used to process to the input and produced the output. Java uses the concept of stream and makes fast I/O operation. The java.io package is the collection of classes which are requires to input and output. We can perform file handling in java by Java I/O API. Stream A stream is a sequence of data.In Java a stream is composed of bytes. It's called a stream because it is like a stream of water that continues to flow. In java, 3 streams are created for us automatically. All these streams are attached with console. 1) System.out: standard output stream 2) System.in: standard input stream 3) System.err: standard error stream System.out.println("simple message"); System.err.println("error message"); int i=System.in.read();//returns ASCII code of 1st character System.out.println((char)i);//will print the character OutputStream Java application uses an output stream to write data to a destination, it may be a file, an array, peripheral device or socket. InputStream Java application uses an input stream to read data from a source, it may be a file, an array, peripheral device or socket. Let's understand working of Java OutputStream and InputStream by the figure given below.
- 65. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 65 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package OutputStream class OutputStream class is an abstract class. It is the super class of all classes representing an output stream of bytes. An output stream accepts output bytes and sends them to some sink. Useful methods of OutputStream Method Description 1) public void write(int)throws IOException is used to write a byte to the current output stream. 2) public void write(byte[])throws IOException is used to write an array of byte to the current output stream. 3) public void flush()throws IOException flushes the current output stream. 4) public void close()throws IOException is used to close the current output stream. OutputStream Hierarchy
- 66. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 66 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package InputStream class InputStream class is an abstract class. It is the super class of all classes representing an input stream of bytes. Useful methods of InputStream Method Description 1) public abstract int read()throws IOException reads the next byte of data from the input stream. It returns -1 at the end of file. 2) public int available()throws IOException returns an estimate of the number of bytes that can be read from the current input stream. 3) public void close()throws IOException is used to close the current input stream. InputStream Hierarchy
- 67. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 67 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package FileOutputStream Class Java FileOutputStream is an output stream used for writing data to a file. If you have to write primitive values into a file, use FileOutputStream class. You can write byte-oriented as well as character-oriented data through FileOutputStream class. But, for character-oriented data, it is preferred to use FileWriter than FileOutStream. FileOutputStream class methods Method Description protected void finalize() It is sued to clean up the connection with the file output stream. void write(byte[] ary) It is used to write ary.length bytes from the byte array to the file output stream. void write(byte[] ary, int off, int len) It is used to write len bytes from the byte array starting at offset off to the file output stream. void write(int b) It is used to write the specified byte to the file output stream. FileChannel getChannel() It is used to return the file channel object associated with the file output stream. FileDescriptor getFD() It is used to return the file descriptor associated with the stream. void close() It is used to closes the file output stream. Java FileOutputStream Example 1: write byte import java.io.FileOutputStream; public class FileOutputStreamExample { public static void main(String args[]){ try{ FileOutputStream fout=new FileOutputStream("D:testout.txt"); fout.write(65); fout.close(); System.out.println("success..."); }catch(Exception e){System.out.println(e);} } } Output: Success...(this is the output which show at consol after the execution of the program)
- 68. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 68 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package The content of a text file testout.txt is set with the data A. testout.txt A (this is data which is written by the program in the testout.txt file) Java FileOutputStream example 2: write string import java.io.FileOutputStream; public class FileOutputStreamExample { public static void main(String args[]){ try{ FileOutputStream fout=new FileOutputStream("D:testout.txt"); String s="Welcome to Aims Tutorial."; byte b[]=s.getBytes();//converting string into byte array fout.write(b); fout.close(); System.out.println("success..."); }catch(Exception e){System.out.println(e);} } } Output: Success... The content of a text file testout.txt is set with the data Welcome to Aims Tutorial. testout.txt Welcome to Aims Tutorial. FileInputStream Class Java FileInputStream class obtains input bytes from a file. It is used for reading byte-oriented data (streams of raw bytes) such as image data, audio, video etc. You can also read character- stream data. But, for reading streams of characters, it is recommended to use FileReader class. Java FileInputStream class methods Method Description int available() It is used to return the estimated number of bytes that can be read from the input stream. int read() It is used to read the byte of data from the input stream. int read(byte[] b) It is used to read up to b.length bytes of data from the input stream. int read(byte[] b, int off, int len) It is used to read up to len bytes of data from the input stream.
- 69. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 69 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package long skip(long x) It is used to skip over and discards x bytes of data from the input stream. FileChannel getChannel() It is used to return the unique FileChannel object associated with the file input stream. FileDescriptor getFD() It is used to return the FileDescriptor object. protected void finalize() It is used to ensure that the close method is call when there is no more reference to the file input stream. void close() It is used to closes the stream. Java FileInputStream example 1: read single character import java.io.FileInputStream; public class DataStreamExample { public static void main(String args[]){ try{ FileInputStream fin=new FileInputStream("D:testout.txt"); int i=fin.read(); System.out.print((char)i); fin.close(); }catch(Exception e){System.out.println(e);} } } Note: Before running the code, a text file named as "testout.txt" is required to be created. In this file, we are having following content: Welcome to Aims Tutorial. After executing the above program, you will get a single character from the file which is 87 (in byte form). To see the text, you need to convert it into character. Output: Welcome to AimsTutorial
- 70. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 70 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package Java FileInputStream example 2: read all characters package com.javatpoint; import java.io.FileInputStream; public class DataStreamExample { public static void main(String args[]){ try{ FileInputStream fin=new FileInputStream("D:testout.txt"); int i=0; while((i=fin.read())!=-1){ System.out.print((char)i); } fin.close(); }catch(Exception e){System.out.println(e);} } } Output: Welcome to Aims Tutorial BufferedOutputStream Class Java BufferedOutputStream class is used for buffering an output stream. It internally uses buffer to store data. It adds more efficiency than to write data directly into a stream. So, it makes the performance fast. For adding the buffer in an OutputStream, use the BufferedOutputStream class. Let's see the syntax for adding the buffer in an OutputStream: OutputStream os= new BufferedOutputStream(new FileOutputStream("D:IO Packag etestout.txt")); Java BufferedOutputStream class constructors Constructor Description BufferedOutputStream(OutputStream os) It creates the new buffered output stream which is used for writing the data to the specified output stream. BufferedOutputStream(OutputStream os, int size) It creates the new buffered output stream which is used for writing the data to the specified output stream with a specified buffer size.
- 71. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 71 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package Java BufferedOutputStream class methods Method Description void write(int b) It writes the specified byte to the buffered output stream. void write(byte[] b, int off, int len) It write the bytes from the specified byte-input stream into a specified byte array, starting with the given offset void flush() It flushes the buffered output stream. Example of BufferedOutputStream class: In this example, we are writing the textual information in the BufferedOutputStream object which is connected to the FileOutputStream object. The flush() flushes the data of one stream and send it into another. It is required if you have connected the one stream with another. package com.javatpoint; import java.io.*; public class BufferedOutputStreamExample{ public static void main(String args[])throws Exception{ FileOutputStream fout=new FileOutputStream("D:testout.txt"); BufferedOutputStream bout=new BufferedOutputStream(fout); String s="Welcome to Aims Tutorial."; byte b[]=s.getBytes(); bout.write(b); bout.flush(); bout.close(); fout.close(); System.out.println("success"); } } Output: Success testout.txt Welcome to Aims Tutorial.
- 72. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 72 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package BufferedInputStream Class Java BufferedInputStream class is used to read information from stream. It internally uses buffer mechanism to make the performance fast. The important points about BufferedInputStream are: When the bytes from the stream are skipped or read, the internal buffer automatically refilled from the contained input stream, many bytes at a time. When a BufferedInputStream is created, an internal buffer array is created. Java BufferedInputStream class constructors Constructor Description BufferedInputStream(InputStream IS) It creates the BufferedInputStream and saves it argument, the input stream IS, for later use. BufferedInputStream(InputStream IS, int size) It creates the BufferedInputStream with a specified buffer size and saves it argument, the input stream IS, for later use. Java BufferedInputStream class methods Method Description int available() It returns an estimate number of bytes that can be read from the input stream without blocking by the next invocation method for the input stream. int read() It read the next byte of data from the input stream. int read(byte[] b, int off, int ln) It read the bytes from the specified byte-input stream into a specified byte array, starting with the given offset. void close() It closes the input stream and releases any of the system resources associated with the stream. void reset() It repositions the stream at a position the mark method was last called on this input stream. void mark(int readlimit) It sees the general contract of the mark method for the input stream.
- 73. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 73 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package long skip(long x) It skips over and discards x bytes of data from the input stream. boolean markSupported() It tests for the input stream to support the mark and reset methods. Example of Java BufferedInputStream package com.javatpoint; import java.io.*; public class BufferedInputStreamExample { public static void main(String args[]) { try{ FileInputStream fin=new FileInputStream("D:testout.txt"); BufferedInputStream bin=new BufferedInputStream(fin); int i; while((i=bin.read())!=-1) { System.out.print((char)i); } bin.close(); fin.close(); } catch(Exception e) { System.out.println(e); } } } Here, we are assuming that you have following data in "testout.txt" file: Aims Tutorial Output: Aims Tutorial BufferedWriter Class Java BufferedWriter class is used to provide buffering for Writer instances. It makes the performance fast. It inherits Writer class. The buffering characters are used for providing the efficient writing of single arrays, characters, and strings.
- 74. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 74 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package Class constructors Constructor Description BufferedWriter(Writer wrt) It is used to create a buffered character output stream that uses the default size for an output buffer. BufferedWriter(Writer wrt, int size) It is used to create a buffered character output stream that uses the specified size for an output buffer. Class methods Method Description void newLine() It is used to add a new line by writing a line separator. void write(int c) It is used to write a single character. void write(char[] cbuf, int off, int len) It is used to write a portion of an array of characters. void write(String s, int off, int len) It is used to write a portion of a string. void flush() It is used to flushes the input stream. void close() It is used to closes the input stream Example of Java BufferedWriter Let's see the simple example of writing the data to a text file testout.txt using Java BufferedWriter. package com.aims; import java.io.*; public class BufferedWriterExample { public static void main(String[] args) throws Exception { FileWriter writer = new FileWriter("D:testout.txt"); BufferedWriter buffer = new BufferedWriter(writer); buffer.write("Welcome to Aims Tutorial."); buffer.close(); System.out.println("Success"); } }
- 75. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 75 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package Output: success testout.txt: Welcome to Aims Tutorial. BufferedReader Class Java BufferedReader class is used to read the text from a character-based input stream. It can be used to read data line by line by readLine() method. It makes the performance fast. It inherits Reader class. Java BufferedReader class constructors Constructor Description BufferedReader(Reader rd) It is used to create a buffered character input stream that uses the default size for an input buffer. BufferedReader(Reader rd, int size) It is used to create a buffered character input stream that uses the specified size for an input buffer. Java BufferedReader class methods Method Description int read() It is used for reading a single character. int read(char[] cbuf, int off, int len) It is used for reading characters into a portion of an array. boolean markSupported() It is used to test the input stream support for the mark and reset method. String readLine() It is used for reading a line of text. boolean ready() It is used to test whether the input stream is ready to be read. long skip(long n) It is used for skipping the characters. void reset() It repositions the stream at a position the mark method was last called on this input stream.
- 76. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 76 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] Java.io package void mark(int readAheadLimit) It is used for marking the present position in a stream. void close() It closes the input stream and releases any of the system resources associated with the stream. Java BufferedReader Example In this example, we are reading the data from the text file testout.txt using Java BufferedReader class. package com.javatpoint; import java.io.*; public class BufferedReaderExample { public static void main(String args[])throws Exception { FileReader fr=new FileReader("D:testout.txt"); BufferedReader br=new BufferedReader(fr); int i; while((i=br.read())!=-1) { System.out.print((char)i); } br.close(); fr.close(); } } Here, we are assuming that you have following data in "testout.txt" file: Welcome to Aims Tutorial. Output: Welcome to Aims Tutorial.
- 77. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 77 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI GUI GUI stands for Graphical User Interface. It is a type of interface which allow user to interact with computer. It is used windows, menus , icons which can be manipulated by mouse. What is GUI programming? Programming application which used such as windows, menus, icon, labels, this type of applications development are known as GII programming. GUI programming in java We can make GUI application using AWT(Abstract window toolkit), Swing , JavaFx , this is the readymade API(application interface) which provide a rich set of classes and interface. So the developer can developed GUI using these API’S. AWT(Abstract Window tool kit) Java AWT (Abstract Window Toolkit) is an API to develop GUI or window-based applications in java. Java AWT components are platform-dependent i.e. components are displayed according to the view of operating system. AWT is heavyweight i.e. its components are using the resources of OS. The java.awt package provides classes for AWT api such as TextField, Label, TextArea, RadioButton, CheckBox, Choice, List etc. It is a package in which the collection of classes and interfaces from which developer can make GUI application component : - Component is an object which is displayed pictorially on the screen. Ex:- Button,Label,TextField......etc Container:- Container is a GUI component, it is able to accommodate all other GUI components. Ex:- Frame,Applet. Event:- The event nothing but a action generated on the component or the change is made on the state of the object. Ex:- Button clicked, Checkboxchecked, Itemselected in the list, Scrollbar scrolled horizontal/vertically.
- 78. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 78 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI Java AWT Hierarchy The hierarchy of Java AWT classes are given below. Frame 1) Frame is a class which is present in java.awt package. 2) Frame is a Basic component in AWT, because all the components displayed in a Frame. 3) We are displaying pictures on the Frame. 4) It is possible to display some text on the Frame. Based on the above reasons the frame will become basic component in AWT. Constructors:- * create a Frame class object. Frame f=new Frame(); * create a Frame class object and pass file Frame f=new Frame("MyFrame"); * Take a subclass to the Frame and create object to the subclass. class MyFrame extends Frame MyFrame f=new MyFrame(); Characteristics of the Frame:- 1) When we create a Frame class object the Frame will be created automatically with the invisible mode. To provide visible mode to following method.
- 79. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 79 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI public void setVisible(boolean b) where b==true means visible mode. where b==false means invisible mode. Ex: f.setVisible(true); public void setSize(int width,int height) Ex: f.setSize(400,500); 3) To provide title to the Frame explicitly we have to use the following method public void setTitle(String Title) Ex: f.setTitle("MyFrame"); 4) When we create a Frame, the default background color of the Frame is white. If you want to provide particular color to the Frame we have to use the following method. public void setBackground(color c) Ex: f.setBackground(Color.red); ********CREATION OF FRMAE********** import java.awt.*; class Demo { public static void main(String[] args) { //frame creation Frame f=new Frame(); //set visibility f.setVisible(true); //set the size of the frame f.setSize(400,400); //set the background f.setBackground(Color.red); //set the title of the frame f.setTitle("Aims Tutorial"); } };
- 80. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 80 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI Preparation of the components Label 1) Label is a constant text which is displayed along with a TextField or TextArea. 2) Label is a class which is present in java.awt package. 3) To display the label we have to add that label into the frame for that purpose we have to use add() method present in the Frame class. Constructor Label l=new Label(); Label l=new Label(“user name”); Ex :- import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("Aims"); f.setBackground(Color.red); f.setSize(400,500); Label l=new Label("user name:"); f.add(l); } } TextField 1) TextField is an editable area. 2) In TextField we are able to provide single line of text. 3) Enter Button doesn’t work on TextField. To add TextField into the Frame we have to use add() method. 1. To set Text to the textarea we have to use the following method. t.setText(“Aims”); 2. To get the text form the TextArea we have to use fallowing method. String s=t.getText(); 3. To append the text into the TextArea. t.appendText("Tutorial");
- 81. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 81 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI Constructor:- TextFiled tx=new TextFiled(); TextField tx=new TextField(“Aims”); Ex :- import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("Aims"); f.setBackground(Color.red); f.setSize(400,500); //TextField tx=new TextField(); empty TextField TextField tx=new TextField("Manish"); //TextField with data f.add(tx); } } TextArea 1) TextArea is a class present in java.awt.package. 2) TextArea is a Editable Area. Enter button will work on TextArea. 3) To add the TextArea into the frame we have to use the add() Construction:- TextArea t=new TextArea(); TextArea t=new TextArea(int rows,int columns); 4. To set Text to the textarea we have to use the following method. t.setText(“Aims Tutorial”); 5. To get the text form the TextArea we have to use fallowing method. String s=t.getText();
- 82. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 82 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI 6. To append the text into the TextArea. t.appendText("Tutorial"); import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("AimsTutorial"); f.setBackground(Color.red); f.setSize(400,500); f.setLayout(new FlowLayout()); Label l=new Label("user name:"); TextArea tx=new TextArea(4,10);//4 character height 10 character width tx.appendText("Manish"); tx.setText("Soni"); System.out.println(tx.getText()); f.add(l); f.add(tx); } } Choice 1) Choice is a class present in java.awt package. 2) List is allows to select multiple items but choice is allow to select single Item. Constructor:- Choice ch=new Choice(); Methods :- 1. To add items to the choice we have to use following method. ch.add(“HYD”); ch.add(“Chennai”); ch.add(“BANGALORE”); 2. To remove item from the choice based on the string. ch.remove(“HYD”); ch.remove(“BANGALORE”);
- 83. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 83 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI 3. To remove the item based on the index position ch.remove(2); 4. To remove the all elements ch.removeAll(); 5. To inset the data into the choice based on the particular position. ch.insert(2,”ratan”); 6. To get selected item from the choice we have to use following method. String s=ch.getSelectedItem(); 7. To get the selected item index number we have to use fallowing method int a=ch.getSelectedIndex(); ex:- import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("AimsTutorial"); f.setBackground(Color.red); f.setSize(400,500); Choice ch=new Choice(); ch.add("c"); ch.add("cpp"); ch.add("java"); ch.add(".net"); ch.remove(".net"); ch.remove(0); ch.insert("Manish",0); f.add(ch); System.out.println(ch.getItem(0)); System.out.println(ch.getSelectedItem()); System.out.println(ch.getSelectedIndex()); //ch.removeAll(); } }
- 84. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 84 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI List 1) List is a class it is present in java.awt.package 2) List is providing list of options to select. Based on your requirement we can select any number of elements. To add the List to the frame we have to use add() method. CONSTRUCTOR:- 1) List l=new List(); It will creates the list by default size is four elements. And it is allow selecting the only one item at a time. 2) List l=new List(3); It will display the three items size and it is allow selecting the only single item. 3) List l=new List(5,true); It will display the five items and it is allow selecting the multiple items. Methods:- 1. To add the elements to the List we have to use following method. l.add(“c”); l.add(“cpp”); l.add(“java”); l.add(“Manish”,0); 2. To remove element from the List we have to use following method. l.remove(“c”); l.remove(2); 3. To get selected item from the List we have to use following method. String x=l.get SelectedItem(); 4. To get selected items from the List we have to use following method. String[] x=s.get SelectedItems() Ex:- import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("ratan"); f.setBackground(Color.red); f.setSize(400,500); f.setLayout(new FlowLayout()); List l=new List(4,true); l.add("c");
- 85. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 85 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI l.add("cpp"); l.add("java"); l.add(".net"); l.add("ratan"); l.add("arun",0); l.remove(0); f.add(l); System.out.println(l.getSelectedItem()); } } Checkbox:- 1) Checkbox is a class present in java.awt package. 2) The user can select more than one checkbox at a time. To add the checkbox to the frame we have to use add() method. Constructor:- 1) Checkbox cb1=new CheckBox(); cb1.setLable(“BTECH”); 2) Checkbox cb1=new CheckBox(“MCA”); 3) Checkbox cb3=new CheckBox(“BSC”,true); Methods:- 1. To set a label to the CheckBox explicitly and to get label from the CheckBox we have to use the following method. cb.setLabel(“BSC”); 2. To get the label of the checkbox we have to use fallowing method. String str=cb.getLabel(); 3. To get state of the CheckBox and to set state to the CheckBox we have to use following method. Boolean b=ch.getState(); Ex:- import java.awt.*; class Test { public static void main(String[] args) {
- 86. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 86 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI Frame f=new Frame(); f.setVisible(true); f.setTitle("Aims Tutorial"); f.setBackground(Color.red); f.setSize(400,500); Checkbox cb1=new Checkbox("BTECH",true); f.add(cb1); System.out.println(cb1.getLabel()); System.out.println(cb1.getState()); } } RADIO BUTTON:- 1) AWT does not provide any predefined support to create RadioButtons. 2) It is possible to select Only item is selected from group of item. To add the RadioButton to the frame we have to use add() method. By using two classes we create Radio Button those are a)CheckBoxgroup b)CheckBox step 1:- Create CheckBox group object. CheckBoxGroup cg=new CheckBoxGroup(); step 2:- pass Checkbox object to the CheckboxGroup class then the radio buttons are created. CheckBox cb1=new CheckBox(“male”,cg,false); CheckBox cb2=new CheckBox(“female”,cg,false); Methods:- 1) To set status and to get status we have to use setState() and getState() methods. String str=Cb.getState(); Cb.setState(); 2) To get Label and to set Label we have to use following methods. String str=getLabel() setLabel(“female”). Ex:- import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("Aims Tutorial"); f.setBackground(Color.red); f.setSize(400,500);
- 87. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 87 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI CheckboxGroup cg=new CheckboxGroup(); Checkbox cb1=new Checkbox("male",cg,true); f.add(cb1); System.out.println(cb1.getLabel()); System.out.println(cb1.getState()); } } Layout Managers:- import java.awt.*; class Test { public static void main(String[] args) { Frame f=new Frame(); f.setVisible(true); f.setTitle("Aims Tutorial"); f.setBackground(Color.red); f.setSize(400,500); Label l1=new Label("user name:"); TextField tx1=new TextField(); Label l2=new Label("password:"); TextField tx2=new TextField(); Button b=new Button("login"); f.add(l1); f.add(tx1); f.add(l2); f.add(tx1); f.add(b); } } Event delegation model:- 1. When we create a component the components visible on the screen but it is not possible to perform any action for example button. 2. Whenever we create a Frame it can be minimized and maximized and resized but it is not possible to close the Frame even if we click on Frame close Button. 3. The Frame is a static component so it is not possible to perform actions on the Frame. 4. To make static component into dynamic component we have to add some actions to the Frame. 5. To attach actions to the Frame component we need event delegation model.
- 88. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 88 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI Whenever we click on button no action will be performed clicking like this is called event. Event: - Event is nothing but a particular action generated on the particular component. 1. When an event generates on the component the component is unable to respond because component can't listen the event. 2. To make the component listen the event we have to add listeners to the component. 3. Wherever we are adding listeners to the component the component is able to respond based on the generated event. 4. A listener is a interface which contain abstract methods and it is present in java.awt.event package 5. The listeners are different from component to component. A component delegate event to the listener and listener is designates the event to appropriate method by executing that method only the event is handled. This is called Event Delegation Model. Handling method Added listener to the component Delegates Handling method listeners component Delegates Delegates Delegates Click the button(event is raised) Handling method Note: - To attach a particular listener to the Frame we have to use following method Public void AddxxxListener(xxxListener e) Where xxx may be ActionListener,windowListener The Appropriate Listener for the Frame is “windowListener” ScrollBar:- 1. ScrollBar is a class present in the java.qwt.package 2. By using ScrollBar we can move the Frame up and down. ScrollBar s=new ScrollBar(int type) Type of scrollbar 1. VERTICAL ScrollBar 2. HORIZONTAL ScrollBar
- 89. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 89 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI To create a HORIZONTAL ScrollBar:- ScrollBar sb=new ScrollBar(ScrollBar.HORIZONTAL); To get the current position of the scrollbar we have to use the following method. public int getValue() To create a VERTICAL ScrollBar:- ScrollBar sb=new ScrollBar(ScrollBar.VERTICAL); Appropriate Listeners for Components:- GUI Component Event Name Listner Name Lisener Methods ____________ __________ ____________ _______________ 1.Frame Window Event Window Listener 1.Public Void WindowOpened(WindowEvent e) 2.Public Void WindowActivated(WindowEvent e) 3.Public Void WindowDeactivated(WindowEvent e) 4.Public Void WindowClosing(WindowEvent e) 5.Public Void WindowClosed(WindowEvent e) 6.Public Void WindowIconfield(WindowEvent e) 7.Public Void WindowDeiconified(WindowEvent e) 2.Textfield ActionEvent ActionListener 1.Public Void Actionperformed(ActionEvent ae) 3.TextArea ActionEvent ActionListener 1.Public Void Actionperformed(ActionEvent ae) 4.Menu ActionEvent ActionListener 1.Public Void Actionperformed(ActionEvent ae) 5.Button ActionEvent ActionListener 1.Public Void Actionperformed(ActionEvent ae) 6.Checkbox ItemEvent ItemListener 1.Public Void ItemStatechanged(ItemEvent e) 7.Radio ItemEvent ItemListener 1.Public Void ItemStatechanged(ItemEvent e) 8.List ItemEvent ItemListener 1.Public Void ItemStatechanged(ItemEvent e) 9.Choice ItemEvent ItemListener 1.Public Void ItemStatechanged(ItemEvent e) 10.Scrollbar AdjustmentEvent AdjustmentListener 1.Public Void AdjustementValueChanged (AdjustementEvent e) 11.Mouse MouseEvent MouseListener 1.Public Void MouseEntered(MouseEvent e) 2.Public Void MouseExited(MouseEvent e) 3.Public Void MousePressed(MouseEvent e) 4.Public Void MouseReleased(MouseEvent e) 5.Public Void MouseClicked(MouseEvent e) 12.Keyboard KeyEvent KeyListener 1.Public Void KeyTyped(KeyEvent e) 2.Public Void KeyPressed(KeyEvent e) 3.Public Void KeyReleased(KeyEvent e)
- 90. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 90 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI ***PROVIDING CLOSING OPTION TO THE FRAME**** import java.awt.*; import java.awt.event.*; class MyFrame extends Frame { MyFrame() { this.setSize(400,500); this.setVisible(true); this.setTitle("myframe"); this.addWindowListener(new myclassimpl()); } } class myclassimpl implements WindowListener { public void windowActivated(WindowEvent e) { System.out.println("window activated"); } public void windowDeactivated(WindowEvent e) { System.out.println("window deactivated"); } public void windowIconified(WindowEvent e) { System.out.println("window iconified"); } public void windowDeiconified(WindowEvent e) { System.out.println("window deiconified"); } public void windowClosed(WindowEvent e) { System.out.println("window closed"); } public void windowClosing(WindowEvent e) { System.exit(0); }
- 91. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 91 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI public void windowOpened(WindowEvent e) { System.out.println("window Opened"); } }; class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; **PROVIDING CLOSEING OPTION TO THE FRAME*** import java.awt.*; import java.awt.event.*; class MyFrame extends Frame { MyFrame() { this.setVisible(true); this.setSize(500,500); this.setBackground(Color.red); this.setTitle("Aims Tutoiral"); this.addWindowListener(new Listenerimpl()); } }; class Listenerimpl extends WindowAdapter { public void windowClosing(WindowEvent we) { System.exit(0); } }; class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } };
- 92. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 92 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI Note ;- by using WindowAdaptor class we can close the frame. Internally WindowAdaptor class implements WindowListener interface. Hence WindowAdaptor class contains empty implementation of abstract methods. ****PROVIDING CLOSEING OPTION THE FRAME****** import java.awt.*; import java.awt.event.*; class MyFrame extends Frame { MyFrame() { this.setVisible(true); this.setSize(500,500); this.setBackground(Color.red); this.setTitle("trialAims T"); this.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent we) { System.exit(0); } }); } } class FrameEx { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ***WRITE SOME TEXT INTO THE FRAME******** import java.awt.*; class MyFrame extends Frame { MyFrame() { this.setVisible(true); this.setSize(500,500); this.setBackground(Color.red); this.setTitle("rattaiah"); } public void paint(Graphics g) { Font f=new Font("arial",Font.BOLD,20); g.setFont(f); this.setForeground(Color.green); g.drawString("HI BTECH ",100,100); g.drawString("good boys &",200,200); g.drawString("good girls",300,300);
- 93. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 93 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI } } class FrameEx { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ------------------------------------------------ ********LAYOUT MACHANISUMS FLOWLAYOUT********** import java.awt.*; import java.awt.event.*; class MyFrame extends Frame { Label l1,l2; TextField tx1,tx2; Button b; MyFrame() { this.setVisible(true); this.setSize(340,500); this.setBackground(Color.green); this.setTitle("Aims Tutorial"); l1=new Label("user name:"); l2=new Label("password:"); tx1=new TextField(25); tx2=new TextField(25); b=new Button("login"); tx2.setEchoChar('*'); this.setLayout(new FlowLayout()); this.add(l1); this.add(tx1); this.add(l2); this.add(tx2); this.add(b); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } };
- 94. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 94 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI ---------------------------------------------------- *****BORDERLAYOUT********** import java.awt.*; class MyFrame extends Frame { Button b1,b2,b3,b4,b5; MyFrame() { this.setBackground(Color.green); this.setSize(400,400); this.setVisible(true); this.setLayout(new BorderLayout()); b1=new Button("Boys"); b2=new Button("Girls"); b3=new Button("management"); b4=new Button("Teaching Staff"); b5=new Button("non-teaching staff"); this.add("North",b1); this.add("Center",b2); this.add("South",b3); this.add("East",b4); this.add("West",b5); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; --------------------------------------------------- ********CardLayout************* import java.awt.*; class MyFrame extends Frame { MyFrame() { this.setSize(400,400); this.setVisible(true); this.setLayout(new CardLayout()); Button b1=new Button("button1"); Button b2=new Button("button2"); Button b3=new Button("button3"); Button b4=new Button("button4"); Button b5=new Button("button5"); this.add("First Card",b1); this.add("Second Card",b2);
- 95. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 95 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI this.add("Thrid Card",b3); this.add("Fourth Card",b4); this.add("Fifth Card",b5); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ********GRIDLAYOUT********** import java.awt.*; class MyFrame extends Frame { MyFrame() { this.setVisible(true); this.setSize(500,500); this.setTitle("rattaiah"); this.setBackground(Color.red); this.setLayout(new GridLayout(4,4)); for (int i=0;i<10 ;i++ ) { Button b=new Button(""+i); this.add(b); } }; class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; *********ACTIONLISTENER********** import java.awt.*; import java.awt.event.*; class myframe extends Frame implements ActionListener { TextField tx1,tx2,tx3; Label l1,l2,l3; Button b1,b2; int result; myframe() { this.setSize(250,400); this.setVisible(true); this.setLayout(new FlowLayout());
- 96. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 96 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI l1=new Label("first value"); l2=new Label("second value"); l3=new Label("result"); tx1=new TextField(25); tx2=new TextField(25); tx3=new TextField(25); b1=new Button("add"); b2=new Button("mul"); b1.addActionListener(this); b2.addActionListener(this); this.add(l1); this.add(tx1); this.add(l2); this.add(tx2); this.add(l3); this.add(tx3); this.add(b1); this.add(b2); } public void actionPerformed(ActionEvent e) { try{ int fval=Integer.parseInt(tx1.getText()); int sval=Integer.parseInt(tx2.getText()); String label=e.getActionCommand(); if (label.equals("add")) { result=fval+sval; } if (label.equals("mul")) { result=fval*sval; } tx3.setText(""+result); } catch(Exception ee) { ee.printStackTrace(); } } }; class Demo { public static void main(String[] args) { myframe f=new myframe(); } };
- 97. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 97 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI ------------------------------------------------------------------------------------------------------------------------ ---------------- ***** LOGIN STATUS********* import java.awt.*; import java.awt.event.*; class MyFrame extends Frame implements ActionListener { Label l1,l2; TextField tx1,tx2; Button b; String status=""; MyFrame() { setVisible(true); setSize(400,400); setTitle("girls"); setBackground(Color.red); l1=new Label("user name:"); l2=new Label("password:"); tx1=new TextField(25); tx2=new TextField(25); b=new Button("login"); b.addActionListener(this); tx2.setEchoChar('*'); this.setLayout(new FlowLayout()); this.add(l1); this.add(tx1); this.add(l2); this.add(tx2); this.add(b); } public void actionPerformed(ActionEvent ae) { String uname=tx1.getText(); String upwd=tx2.getText(); if (uname.equals("durga")&&upwd.equals("dss")) { status="login success"; } else { status="login failure"; } repaint(); } public void paint(Graphics g) { Font f=new Font("arial",Font.BOLD,30); g.setFont(f);
- 98. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 98 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI this.setForeground(Color.green); g.drawString("Status:----"+status,50,300); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ------------------------------------------------------------------------------------------------------------------------ ---------------- ******MENUITEMS************ import java.awt.*; import java.awt.event.*; class MyFrame extends Frame implements ActionListener { String label=""; MenuBar mb; Menu m1,m2,m3; MenuItem mi1,mi2,mi3; MyFrame() { this.setSize(300,300); this.setVisible(true); this.setTitle("myFrame"); this.setBackground(Color.green); mb=new MenuBar(); this.setMenuBar(mb); m1=new Menu("new"); m2=new Menu("option"); m3=new Menu("edit"); mb.add(m1); mb.add(m2); mb.add(m3); mi1=new MenuItem("open"); mi2=new MenuItem("save"); mi3=new MenuItem("saveas"); mi1.addActionListener(this); mi2.addActionListener(this); mi3.addActionListener(this); m1.add(mi1); m1.add(mi2); m1.add(mi3); } public void actionPerformed(ActionEvent ae) { label=ae.getActionCommand();
- 99. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 99 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI repaint(); } public void paint(Graphics g) { Font f=new Font("arial",Font.BOLD,25); g.setFont(f); g.drawString("Selected item....."+label,50,200); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ------------------------------------------------------------------------------------------------------------------------ ---------------- *****MOUSELISTENER INTERFACE********** import java.awt.*; import java.awt.event.*; class myframe extends Frame implements MouseListener { String[] msg=new String[5]; myframe() { this.setSize(500,500); this.setVisible(true); this.addMouseListener(this); } public void mouseClicked(MouseEvent e) { msg[0]="mouse clicked......("+e.getX()+","+e.getY()+")"; repaint(); } public void mousePressed(MouseEvent e) { msg[1]="mouse pressed......("+e.getX()+","+e.getY()+")"; repaint(); } public void mouseReleased(MouseEvent e) { msg[2]="mouse released......("+e.getX()+","+e.getY()+")"; repaint(); } public void mouseEntered(MouseEvent e) { msg[3]="mouse entered......("+e.getX()+","+e.getY()+")"; repaint();
- 100. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 100 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI } public void mouseExited(MouseEvent e) { msg[4]="mouse exited......("+e.getX()+","+e.getY()+")"; repaint(); } public void paint(Graphics g) { int X=50; int Y=100; for(int i=0;i<msg.length;i++) { if (msg[i]!=null) { g.drawString(msg[i],X,Y); Y=Y+50; } } } }; class Demo { public static void main(String[] args) { myframe f=new myframe(); } }; ------------------------------------------------------------------------------------------------------------------------ ---------------- *******ITEMLISTENER INTERFACE********** import java.awt.*; import java.awt.event.*; class myframe extends Frame implements ItemListener { String qual="",gen=""; Label l1,l2; CheckboxGroup cg; Checkbox c1,c2,c3,c4,c5; Font f; myframe() { this.setSize(300,400); this.setVisible(true); this.setLayout(new FlowLayout()); l1=new Label("Qualification: "); l2=new Label("Gender: "); c1=new Checkbox("BSC"); c2=new Checkbox("BTECH"); c3=new Checkbox("MCA");
- 101. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 101 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI cg=new CheckboxGroup(); c4=new Checkbox("Male",cg,false); c5=new Checkbox("Female",cg,true); c1.addItemListener(this); c2.addItemListener(this); c3.addItemListener(this); c4.addItemListener(this); c5.addItemListener(this); this.add(l1); this.add(c1); this.add(c2); this.add(c3); this.add(l2); this.add(c4); this.add(c5); } public void itemStateChanged(ItemEvent ie) { if(c1.getState()==true) { qual=qual+c1.getLabel()+","; } if(c2.getState()==true) { qual=qual+c2.getLabel()+","; } if(c3.getState()==true) { qual=qual+c3.getLabel()+","; } if(c4.getState()==true) { gen=c4.getLabel(); } if(c5.getState()==true) { gen=c5.getLabel(); } repaint(); } public void paint(Graphics g) { Font f=new Font("arial",Font.BOLD,20); g.setFont(f); this.setForeground(Color.green); g.drawString("qualification------>"+qual,50,100); g.drawString("gender-------------->"+gen,50,150); qual=""; gen="";
- 102. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 102 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI } } class rc { public static void main(String[] args) { myframe f=new myframe(); } }; ------------------------------------------------------------------------------------------------------------------------ ---------------- *********KEYLISTENER INTERFACE*********** import java.awt.*; import java.awt.event.*; class myframe extends Frame { myframe() { this.setSize(400,400); this.setVisible(true); this.setBackground(Color.green); this.addKeyListener(new keyboardimpl()); } }; class keyboardimpl implements KeyListener { public void keyTyped(KeyEvent e) { System.out.println("key typed "+e.getKeyChar()); } public void keyPressed(KeyEvent e) { System.out.println("key pressed "+e.getKeyChar()); } public void keyReleased(KeyEvent e) { System.out.println("key released "+e.getKeyChar()); } } class Demo { public static void main(String[] args) { myframe f=new myframe(); } };
- 103. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 103 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI --------------------------------------------------------------------------------------------------------------------------------------- ***********CHECK LIST AND CHOICE************ import java.awt.*; import java.awt.event.*; class myframe extends Frame implements ItemListener { Label l1,l2; List l; Choice ch; String[] tech; String city=""; myframe() { this.setSize(300,400); this.setVisible(true); this.setLayout(new FlowLayout()); l1=new Label("Technologies: "); l2=new Label("City: "); l=new List(3,true); l.add("c"); l.add("c++"); l.add("java"); l.addItemListener(this); ch=new Choice(); ch.add("hyd"); ch.add("chenni"); ch.add("Banglore"); ch.addItemListener(this); this.add(l1); this.add(l); this.add(l2); this.add(ch); } public void itemStateChanged(ItemEvent ie) { tech=l.getSelectedItems(); city=ch.getSelectedItem(); repaint(); } public void paint(Graphics g) { Font f=new Font("arial",Font.BOLD,20); g.setFont(f); String utech=""; for(int i=0;i<tech.length ;i++ ) { utech=utech+tech[i]+" "; } g.drawString("tech:-------"+utech,50,200); g.drawString("city---------"+city,50,300);
- 104. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 104 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI utech=""; } } class Demo { public static void main(String[] args) { myframe f=new myframe(); } }; ----------------------------------------------- *********AdjustmentListener********** import java.awt.*; import java.awt.event.*; class myframe extends Frame implements AdjustmentListener { Scrollbar sb; int position; myframe() { this.setSize(400,400); this.setVisible(true); this.setLayout(new BorderLayout()); sb=new Scrollbar(Scrollbar.VERTICAL); this.add("East",sb); sb.addAdjustmentListener(this); } public void adjustmentValueChanged(AdjustmentEvent e) { position=sb.getValue(); } public void paint(Graphics g) { g.drawString("position:"+position,100,200); repaint(); } } class scrollbarex { public static void main(String[] args) { myframe f=new myframe(); } };
- 105. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 105 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI SWINGS 1. Sun Micro Systems introduced AWT to prepare GUI applications. 2. awt components not satisfy the client requirement. 3. An alternative to AWT Netscape Communication has provided set of GUI components in the form of IFC(Internet Foundation Class). 4. IFC also provide less performance and it is not satisfy the client requirement. 5. In the above contest[sun+Netscape] combine and introduced common product to design GUI applications. Differences between awt and Swings: 1. AWT components are heavyweight component but swing components are light weight component. 2. AWT components consume more number of system resources Swings consume less number of system resources. 3. AWT components are platform dependent but Swings are platform independent. 4. AWT is provided less number of components where as swings provides more number of components. 5. AWT doesn’t provide Tooltip Test support but swing components have provided Tooltip test support. 6. in awt for only window closing : windowListener windowAdaptor In case of swing use small piece of code. i. f.setDefaultCloseOption(JFrame.EXIT-ON-CLOSE); 7. AWT will not follow MVC but swing follows MVC Model View Controller It is a design pattern to provide clear separation b/w controller part,model part,view part. a. Controller is a normal java class it will provide controlling. b. View part provides presentation c. Model part provides required logic.
- 106. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 106 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI 8. In case of AWT we will add the GUI components in the Frame directly but Swing we will add all GUI components to panes to accommodate GUI components. Classes of swing:- ******************SWING********************* import java.awt.*; import javax.swing.*; class MyFrame extends JFrame { JLabel l1,l2,l3,l4,l5,l6,l7; JTextField tf; JPasswordField pf; JCheckBox cb1,cb2,cb3; JRadioButton rb1,rb2; JList l; JComboBox cb; JTextArea ta; JButton b; Container c; MyFrame() { this.setVisible(true); this.setSize(150,500); this.setTitle("SWING GUI COMPONENTS EXAMPLE"); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); c=this.getContentPane(); c.setLayout(new FlowLayout()); c.setBackground(Color.green); l1=new JLabel("User Name"); l2= new JLabel("password"); l3= new JLabel("Qualification"); l4= new JLabel("User Gender"); l5= new JLabel("Technologies"); l6= new JLabel("UserAddress"); l7= new JLabel("comments"); tf=new JTextField(15); tf.setToolTipText("TextField"); pf=new JPasswordField(15); pf.setToolTipText("PasswordField"); cb1=new JCheckBox("BSC",false); cb2=new JCheckBox("MCA",false); cb3=new JCheckBox("PHD",false); rb1=new JRadioButton("Male",false); rb2=new JRadioButton("Female",false);
- 107. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 107 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI ButtonGroup bg=new ButtonGroup(); bg.add(rb1); bg.add(rb2); String[] listitems={"cpp","c","java"}; l=new JList(listitems); String[] cbitems={"hyd","pune","bangalore"}; cb=new JComboBox(cbitems); ta=new JTextArea(5,20); b=new JButton("submit"); c.add(l1); c.add(tf); c.add(l2); c.add(pf); c.add(l3); c.add(cb1); c.add(cb2); c.add(cb3); c.add(l4); c.add(rb1); c.add(rb2); c.add(l5); c.add(l); c.add(l6); c.add(cb); c.add(l7); c.add(ta); c.add(b); } } class SwingDemo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ---------------------------------------------------------------------------------------------------------------------------------------- ********JCOLORCHOOSER*********** import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; class MyFrame extends JFrame implements ChangeListener { JColorChooser cc; Container c; MyFrame() { this.setVisible(true); this.setSize(500,500); this.setTitle("SWING GUI COMPONENTS EXAMPLE");
- 108. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 108 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); c=getContentPane(); cc=new JColorChooser(); cc.getSelectionModel().addChangeListener(this); c.add(cc); } public void stateChanged(ChangeEvent c) { Color color=cc.getColor(); JFrame f=new JFrame(); f.setSize(400,400); f.setVisible(true); f.getContentPane().setBackground(color); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ********JFILECHOOSER********************* import java.io.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; class MyFrame extends JFrame implements ActionListener { JFileChooser fc; Container c; JLabel l; JTextField tf; JButton b; MyFrame() { this.setVisible(true); this.setSize(500,500); this.setTitle("SWING GUI COMPONENTS EXAMPLE"); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); c=getContentPane(); l=new JLabel("Select File:"); tf=new JTextField(25); b=new JButton("BROWSE"); this.setLayout(new FlowLayout()); b.addActionListener(this); c.add(l); c.add(tf); c.add(b);
- 109. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 109 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI } public void actionPerformed(ActionEvent ae) { class FileChooserDemo extends JFrame implements ActionListener { FileChooserDemo() { Container c=getContentPane(); this.setVisible(true); this.setSize(500,500); fc=new JFileChooser(); fc.addActionListener(this); fc.setLayout(new FlowLayout()); c.add(fc); } public void actionPerformed(ActionEvent ae) { File f=fc.getSelectedFile(); String path=f.getAbsolutePath(); tf.setText(path); this.setVisible(false); } } new FileChooserDemo(); } } class Demo { public static void main(String[] args) { MyFrame f=new MyFrame(); } }; ----------------------------------------- ********JTABLE****************** import javax.swing.*; import java.awt.*; import javax.swing.table.*; class Demo1 { public static void main(String[] args) { JFrame f=new JFrame(); f.setVisible(true); f.setSize(300,300); Container c=f.getContentPane(); String[] header={"ENO","ENAME","ESAL"}; Object[][] body={{"111","aaa",5000},{"222","bbb",6000},{"333","ccc",7000},{"444","ddd",8000}}; JTable t=new JTable(body,header); JTableHeader th=t.getTableHeader(); c.setLayout(new BorderLayout());
- 110. Aims Tutorial Oriental Bank of Commerce H.No.:69/339 VT Road Ward 27, Mansarovar Jaipur (Rajasthan) 302020 Contact No: +91-8947920041 P a g e | 110 By: Manish Swarnkar 9887474850 Java Tutorial By:Manish Swarnkar Contact No:9887474850 [email protected] GUI c.add("North",th); c.add("Center",t); } }