Coders Packet

Interface in Java

By Aryan Pradhan

In this tutorial we will learn about the concept of Interface in java. We learn about interface through a simple code.

What is Interface?

The interface. is a blueprint of classes. An interface is a method to achieve 100% abstraction and multiple inheritance. An interface can have methods and variables only. An interface can have only abstract methods, not the body of the method. An interface specifies what a class must do and not what to do. Since java does not support multiple inheritance we can achieve it through the interface.The interface represents the IS-A relationship.


  1. interface  interface_name{  
  3.     // declare constant fields  
  4.     // declare methods that abstract   
  5.     // by default.  
  6. }  

Use of Interface

1. By using the interface we can achieve multiple inheritance.

2. Interface is used to achieve 100% abstraction.

3. It can also be used to achieve loose coupling.



interface shape{

void draw();


class rectangle implements shape{

public void draw(){

System.out.println("Drawing Rectangle");

class square implements shape{

public void draw(){

System.out.println("Drawing Square");


class sample{

public static void main(String args []){

shape s=new square();




Drawing Square

Download Complete Code


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