![Example
abstract class A
{
abstract void run();
void display()
{
System.out.println("Bike");
}
}
class B extends A
{
void run()
{
System.out.println("running safely");
}
public static void main(String args[])
{
B b1 = new B();
b1.run();
b1. display();
}
}](https://image.slidesharecdn.com/bcaabstraction-230414091752-44ead503/85/BCA-Abstraction-pptx-9-320.jpg)
![Example
interface A
{
void print();
}
class B implements A
{
public void print()
{
System.out.println("Hello");
}
public static void main(String a[])
{
B b1 = new B();
b1.print();
}
}](https://image.slidesharecdn.com/bcaabstraction-230414091752-44ead503/85/BCA-Abstraction-pptx-15-320.jpg)
![Multiple inheritance with the help of Interface
interface X
{
void display();
}
interface Y
{
void display();
}
class C implements X, Y
{
public void display()
{
System.out.println("Hello");
}
public static void main(String x[])
{
C c1 = new C();
c1.display();
}
}
Output:
Hello](https://image.slidesharecdn.com/bcaabstraction-230414091752-44ead503/85/BCA-Abstraction-pptx-17-320.jpg)
BCA Abstraction.pptx
- 2. Abstraction in Java • Abstraction is a process of hiding the implementation details and showing only functionality to the user. • For example, sending SMS where you type the text and send the message. You don't know the internal processing about the message delivery.
- 3. Ways to achieve Abstraction • There are two ways to achieve abstraction in java. 1. Abstract class (0 to 100%) 2. Interface (100%)
- 4. 1. Abstract class in Java • A class which is declared as keyword abstract is known as an abstract class. • It can have abstract and non-abstract methods.
- 5. Points to Remember • An abstract class must be declared with an abstract keyword. • It can have abstract and non-abstract methods. • We can not create the object of abstract class.
- 6. Cont… • It needs to be extended in another class and its abstract method should be implemented in that class.
- 7. Example of abstract class abstract class A { }
- 8. Abstract Method in Java • A method which is declared as abstract and does not have body is known as an abstract method. • Example of abstract method abstract void A();//no method body and abstract
- 9. Example abstract class A { abstract void run(); void display() { System.out.println("Bike"); } } class B extends A { void run() { System.out.println("running safely"); } public static void main(String args[]) { B b1 = new B(); b1.run(); b1. display(); } }
- 11. 2. Interface in Java • It has only abstract methods, not method with body. • It is used to achieve 100 % abstraction and multiple inheritance in Java.
- 12. Why use Java interface? • It is used to achieve 100% abstraction. • By interface, we can support the functionality of multiple inheritance.
- 13. Note: • Like abstract classes, object of interfaces can not be created. • It needs to be implements in a class and its method should be implemented in that class. • Interface methods are by default abstract and public.
- 14. Cont… • Interface attributes are by default public, static and final. Example:
- 15. Example interface A { void print(); } class B implements A { public void print() { System.out.println("Hello"); } public static void main(String a[]) { B b1 = new B(); b1.print(); } }
- 17. Multiple inheritance with the help of Interface interface X { void display(); } interface Y { void display(); } class C implements X, Y { public void display() { System.out.println("Hello"); } public static void main(String x[]) { C c1 = new C(); c1.display(); } } Output: Hello