interfaces in java (Abstraction in OOP)

package javaapplication25;





interface shape

{



    void area();

 

}

class square implements shape

{

float s;

 public void area()

 {

     System.out.println("area of square is "+s*s);

 }





}



public class JavaApplication25 {



   

    public static void main(String[] args)

    {

       square s= new square();

        s.s=10;

       s.area();

   

       

    }

   

}