Creating and Implementing Interface:

Interfaces are defined with the following syntax  

[visibility] interface InterfaceName [extends other interfaces]

{

        constant declarations

        method declarations

}

The following program demonstrates the usage of interface. It has a constant named BORDER_WIDTH and a method named ‘draw()’. The class ‘Rectangle’ is implementing the interface and thus providing definition for the method ‘draw()’.

interface Shape

{

      int  BORDER_WIDTH = 5;              

      void draw( );

}

class Rectangle implements Shape

{

    void draw()

     {

        …….

     }

}

               class Test

                            {

                       public static void main(String as[])

                           {

Shape s1;

s1=new Rectangle();

s1.draw();

                     }

                }