![EXAMPLE
public class Hello
{
public static void main(String[] args)
{
System.out.println("Hello Java");
}
}
Program Output:
Hello Java
The above example has been used to print Hello
Java text on the screen.](https://image.slidesharecdn.com/java-190810074349/85/Java-3-320.jpg)
![SIMPLE JAVA PROGRAM
//Name of this file will be "Hello.java"
public class Hello
{
/* Writes the words "Hello Java" on the screen */
public static void main(String[] args)
{
System.out.println("Hello Java");
}
}
Program output:
Hello Java](https://image.slidesharecdn.com/java-190810074349/85/Java-19-320.jpg)
![public static void main •When the main method is declared public, it
means that it can also be used by code
outside of its class, due to which the main
method is declared public.
•The word static used when we want to
access a method without creating its
object, as we call the main method, before
creating any class objects.
•The word void indicates that a method does
not return a value. main() is declared as
void because it does not return a value.
•main is a method; this is a starting point of
a Java program.
You will notice that the main method code
has been moved to some spaces left. It is
called indentation which used to make a
program easier to read and understand.
String[] args It is an array where each element of it is a
string, which has been named as "args". If your
Java program is run through the console, you
can pass input parameter, and main() method
takes it as input.
System.out.println(); This statement is used to print text on the
screen as output, where system is a predefined
class, and out is an object of the PrintWriter
class defined in the system. The
method println prints the text on the screen with
a new line. You can also use print()method](https://image.slidesharecdn.com/java-190810074349/85/Java-21-320.jpg)
![C CPP JAVA
Operator Dot operator Dot Operator Dot Operator
Package Not Create Not Create Create own
Package
Program #include<stdio.h>
//header file for
standard input and
output
main() //ma
in method
{
clrscr(); //clear
the screen
printf(“welcome”); //
print the message
getch(); //get the
character
}
#include<iostream.h
> //header file
necessary for input
output stream
#include<conio.h>
//headerfile for
console input output
main() //main
method
{
clrscr(); //clear the
screen
cout<<”welcome”; /
/cout is used for
output
getch(); //get the
character
}
class
main //program
always start with
class because of
pure object oriented
language
{
public static void
main(String
aa[]) //main method
{
System.out.print(“we
lcome”); //print the
message
}
}](https://image.slidesharecdn.com/java-190810074349/85/Java-23-320.jpg)
Java
- 1. JAVA PROGRAMMING Ms.Snehal Kulthe Department of Management
- 2. INTRODUCTION Required Knowledge Basic Knowledge of C Programming and C++ will help you to understand Java Programming quickly, and If you don't know programming and you are studying Java, so it's quite complicated. Java Example A quick look at the example of Hello Java program and the detailed description is given in Java Program Structure page.
- 3. EXAMPLE public class Hello { public static void main(String[] args) { System.out.println("Hello Java"); } } Program Output: Hello Java The above example has been used to print Hello Java text on the screen.
- 4. Java is an object-oriented programming language with its runtime environment. It is a combination of features of C and C++ with some essential additional concepts. Java is well suited for both standalone and web application development and is designed to provide solutions to most of the problems faced by users of the internet era.
- 5. WHAT IS JAVA Java is an object-oriented programming language developed by Sun Microsystems, and it was released in 1995. James Gosling initially developed Java in Sun Microsystems (which was later merged with Oracle Corporation). Java is a set of features of C and C++. It has obtained its format from C, and OOP features from C++. Java programs are platform independent which means they can be run on any operating system with any processor as long as the Java interpreter is available on that system. Java code that runs on one platform does not need to be recompiled to run on another platform; it's called write once, run anywhere(WORA). Java Virtual Machine (JVM) executes Java code, but it has been written in platform-specific languages such as C/C++/ASM, etc. JVM is not written in Java and hence cannot be platform independent, and Java interpreter is a part of JVM.
- 6. WHERE IS JAVA BEING USED Earlier Java was only used to design and program small computing devices, but it was later adopted as one of the platform-independent programming languages, and now according to Sun, 3 billion devices run Java. Java is one of the most important programming languages in today's IT industries. JSP - In Java, JSP (Java Server Pages) is used to create dynamic web pages, such as in PHP and ASP. Applets - Applets are another type of Java programs that are implemented on Internet browsers and are always run as part of a web document. J2EE - Java 2 Enterprise Edition is a platform-independent environment that is a set of different protocols and APIs and is used by various organizations to transfer data between each other. JavaBeans - This is a set of reusable software components that can be easily used to create new and advanced applications. Mobile - In addition to the above technology, Java is widely used in mobile devices nowadays, many types of games and applications are being made in Java.
- 7. TYPES OF JAVA APPLICATION Web Application - Java is used to create server-side web applications. Currently, Servlet, JSP, Struts, JSF, etc. technologies are used. Standalone Application - It is also known as the desktop application or window-based application. An application that we need to install on every machine or server such as media player, antivirus, etc. AWT and Swing are used in java for creating standalone applications. Enterprise Application - An application that is distributed in nature, such as banking applications, etc. It has the advantage of the high-level security, load balancing, and clustering. In Java, EJB is used for creating enterprise applications. Mobile Application - Java is used to create application software for mobile devices. Currently, Java ME is used for building applications for small devices, and also Java is a programming language for Google Android application development.
- 8. FEATURES OF JAVA Object-Oriented - Java supports the features of object-oriented programming. Its object model is simple and easy to expand. Platform independent - C and C++ are platform dependency languages hence the application programs written in one Operating system cannot run in any other Operating system, but in platform independence language like Java application programs written in one Operating system can able to run on any Operating system. Simple - Java has included many features of C / C ++, which makes it easy to understand. Secure - Java provides a wide range of protection from viruses and malicious programs. It ensures that there will be no damage and no security will be broken. Portable - Java provides us the concept of portability. Running the same program with Java on different platforms is possible. Robust - During the development of the program, it helps us to find possible mistakes as soon as possible. Multi-threaded - The multithreading programming feature in Java allows you to write a program that performs several different tasks simultaneously. Distributed - Java is designed for distributed Internet environments as it manages the TCP/IP protocol. Popular Java Editors
- 9. POPULAR JAVA EDITOR Notepad - On Windows machine, you can use any simple text editor like Notepad (Recommended for this tutorial), TextPad. Netbeans - is a Java IDE that is open source and free which can be downloaded from http://www.netbeans.org/index.html Eclipse - is also a java IDE developed by the Eclipse open source community and can be downloaded from http://www.eclipse.org/
- 10. EVOLUTION OF JAVA The development of each programming language is based on a fact: there is a need to solve a problem that was not resolved by previous programming languages. Early programmers had to choose different programming languages, usually for various tasks, such as a specific language for a type of field. A certain language was sufficient to solve the problems of its field but was not able to solve the problems of other fields. For example, Fortran could have been used to write efficient programs for scientific problems, but it was not good for system code. Similarly, Basic was easy to understand but was not robust to write big programs; While the assembly language was powerful for writing efficient programs, but it was not easy to remember and execution.
- 11. Programming languages such as Cobol, Fortran do not have structural principles. They use the Goto statement to control the flow of the program. Therefore, programs using this type of code are made up of many jumps and conditional statements that make it difficult to understand. Therefore, C was invented in 1970, to replace the assembly language and to create a structured, effective and high-level language. The development of C was the result of the development process started with BCPL by Dennis Ritchie. BCPL is an old language developed by Martin Richard. Ken Thompson developed a language called B, which was influenced by BCPL. C is a processor-oriented programming language; it is easy to execute and understand. C became quite famous at that time because it was reliable, simple and easy to use.
- 12. Though C was quite efficient and successful programming language, the complexity of the program was seeking more efficient language to solve problems. When we write a program in C, it has a limit, such as a maximum of 25000 lines of code, beyond which it can not handle the complexity. But writing and managing large programs was a demand at that time. So a new concept came. C++ came with object-oriented programming features. C++ is the extension of C language which has been used extensively. It is a powerful modern language that includes the power and simplicity of C and the characteristics of OOP. C++ provides more functional software benefits than C. C ++ with OOP became quite famous but then a new problem arose, to control the software on different machines, a separate compiler is required for that CPU. But building a C++ compiler was quite expensive. Therefore, an efficient and easy solution was needed, and this requirement became the reason for the creation of Java, which is a portable and platform-independent language.
- 13. HISTORY OF JAVA TECHNOLOGY History of Java programming language is usually associated with origin predates of the web. James Gosling, Patrick Naughton, Chris Warth, Mike Sheridan and Ed Frank initiated the Java language project in June 1991. The idea was to develop a language which was platform-independent and which could create embedded software for consumer electronic devices. It took 18 months to develop and had an initial name as Oak which was renamed to Java in 1995, due to copyright issues.
- 14. JAVA VERSION RELEASE HISTORY Version Released on JDK1.023 Jan 1996 JDK1.119 Feb 1997 J2SE 1.28 Dec 1998 J2SE 1.38 May 2000 J2SE 1.46 Feb 2002 J2SE 5.030 Sept 2004 Java SE 611 Dec 2006 Java SE 7.028 July 2011 Java SE 8.018 March 2014 Java SE 9.0Sept 2017 Java SE 10 (18.3)2018
- 15. JAVA PROGRAM STRUCTURE It is necessary to know the exact structure of the Java program, and this lesson contains a detailed description of it. This lesson is essential for you before proceeding to learn more advanced lessons of Java programming. Here, in this chapter, you will study the structure of the Java program. Such as how to create a simple Java program and what its different sections mean.
- 16. BASIC STRUCTURE OF JAVA PROGRAM A Java program involves the following sections: Documentation Section Package Statement Import Statements Interface Statement Class Definition Main Method Class Main Method Definition
- 17. Section Description Documentation Section You can write a comment in this section. Comments are beneficial for the programmer because they help them understand the code. These are optional, but we suggest you use them because they are useful to understand the operation of the program, so you must write comments within the program. Package statement You can create a package with any name. A package is a group of classes that are defined by a name. That is, if you want to declare many classes within one element, then you can declare it within a package. It is an optional part of the program, i.e., if you do not want to declare any package, then there will be no problem with it, and you will not get any errors. Here, the package is a keyword that tells the compiler that package has been created.It is declared as: package package_name;
- 18. Import statements This line indicates that if you want to use a class of another package, then you can do this by importing it directly into your program. Example:import calc.add; Interface statement Interfaces are like a class that includes a group of method declarations. It's an optional section and can be used when programmers want to implement multiple inheritances within a program. Class Definition A Java program may contain several class definitions. Classes are the main and essential elements of any Java program. Main Method Class Every Java stand-alone program requires the main method as the starting point of the program. This is an essential part of a Java program. There may be many classes in a Java program, and only one class defines the main method. Methods contain data type declaration and executable statements.
- 19. SIMPLE JAVA PROGRAM //Name of this file will be "Hello.java" public class Hello { /* Writes the words "Hello Java" on the screen */ public static void main(String[] args) { System.out.println("Hello Java"); } } Program output: Hello Java
- 20. public class Hello •This creates a class called Hello. •All class names must start with a capital letter. •The public word means that it is accessible from any other classes. /* Comments */ The compiler ignores comment block. Comment can be used anywhere in the program to add info about program or code block, which will be helpful for developers to understand the existing code in the future easily. Braces Two curly brackets {...} are used to group all the commands, so it is known that the commands belong to that class or method.
- 21. public static void main •When the main method is declared public, it means that it can also be used by code outside of its class, due to which the main method is declared public. •The word static used when we want to access a method without creating its object, as we call the main method, before creating any class objects. •The word void indicates that a method does not return a value. main() is declared as void because it does not return a value. •main is a method; this is a starting point of a Java program. You will notice that the main method code has been moved to some spaces left. It is called indentation which used to make a program easier to read and understand. String[] args It is an array where each element of it is a string, which has been named as "args". If your Java program is run through the console, you can pass input parameter, and main() method takes it as input. System.out.println(); This statement is used to print text on the screen as output, where system is a predefined class, and out is an object of the PrintWriter class defined in the system. The method println prints the text on the screen with a new line. You can also use print()method
- 22. DIFFERENCE OF JAVA C CPP C CPP JAVA Language Procedural Object oriented Pure object Oriented Header file Stdio.h Iostream.h conio.h Java does not support any header file Platform Dependant Dependant Independent Pointers Support Support Does not Support Operator overloading Not used Used Not used Multiple Inheritance Not used Used Instead of this we use Interface Translator Compiler Compiler Compiler and interpreter Web Application Not used Not used Internet programming like Frame,Applet
- 23. C CPP JAVA Operator Dot operator Dot Operator Dot Operator Package Not Create Not Create Create own Package Program #include<stdio.h> //header file for standard input and output main() //ma in method { clrscr(); //clear the screen printf(“welcome”); // print the message getch(); //get the character } #include<iostream.h > //header file necessary for input output stream #include<conio.h> //headerfile for console input output main() //main method { clrscr(); //clear the screen cout<<”welcome”; / /cout is used for output getch(); //get the character } class main //program always start with class because of pure object oriented language { public static void main(String aa[]) //main method { System.out.print(“we lcome”); //print the message } }
- 24. JAVA SUPPORT SYSTEM & ENVIRONMENT The Java Virtual Machine is called JVM, is an abstract computing machine or virtual mac hine interface that drives the java code. When we talk about the Java applications, then it works only on those machines which have JVM.
- 25. WHAT IS JVM JVM i.e., Java Virtual Machine. JVM is the engine that drives the Java code. Mostly in other Programming Languages, compiler produce code for a particular system but Java compiler produce Bytecode for a Java Virtual Machine. When we compile a Java program, then bytecode is generated. Bytecode is the source code that can be used to run on any platform. Bytecode is an intermediary language between Java source and the host system. It is the medium which compiles Java code to bytecode which gets interpreted on a different machine and hence it makes it Platform/Operating system independent.
- 26. JVM'S WORK CAN BE EXPLAINED IN THE FOLLOWING MANNER. Reading Bytecode. Verifying bytecode. Linking the code with the library. Diagram of JVM JVM generates a .class(Bytecode) file, and that file can be run in any OS, but JVM should have in OS because JVM is platform dependent.
- 27. PLATFORM INDEPENDENT Java is called platform independent because of Java Virtual Machine. As different computers with the different operating system have their JVM, when we submit a .class file to any operating system, JVM interprets the bytecode into machine level language. JVM is the main component of Java architecture, and it is the part of the JRE (Java Runtime Environment). A program of JVM is written in C Programming Language, and JVM is Operating System dependent. JVM is responsible for allocating the necessary memory needed by the Java program. JVM is responsible for deallocating memory space.
- 28. Thank You