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Posted on    April-03-2015 12:26 AM

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Mayank Tripathi
Mayank Tripathi

Total Post:807

Posted on    April-03-2015 1:13 AM

An interface in java is a blueprint of a class. It has static constants and abstract methods only.
The interface in java is a mechanism to achieve fully abstractionThere can be only abstract methods in the java interface not method body. It is used to achieve fully abstraction and multiple inheritance in Java.

Java Interface also represents IS-A relationship. It cannot be instantiated just like abstract class.

There are mainly three reasons to use interface. They are given below.

  • 1.It is used to achieve fully abstraction.
  • 2.By interface, we can support the functionality of multiple inheritance.
  • 3.It can be used to achieve loose coupling

The java compiler adds public and abstract keywords before the interface method and public, static and final keywords before data members.In other words, Interface fields are public, static and final bydefault, and methods are public and abstract.

 A class extends another class, an interface extends another interface but a class implements an interface.

Example: Printable interface have only one method, its implementation is provided in the A class
interface printable{  
void print();  
class A6 implements printable{  
public void print(){System.out.println("Hello");}  
public static void main(String args[]){  
A6 obj = new A6();  

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