Polymorphism example in java

class Box

   {

     int w,h;

     void info()

     {

       System.out.println("This is a simple box");

       System.out.println("width = "+ w + " hieght "+ h);

     }

   }

   class WoddenBox extends Box

   {

     int life;

     void info( )

     {

       System.out.println("This is a Wodden box");

     }

   }

   class SteelBox extends Box

   {

     int wg;

     void info( )

     {

       System.out.println("This is a steel box");

     }

   }

   class LargeWoddenBox extends WoddenBox

   {

     void info()

     {

       System.out.println("This is a Huge Wodden box");

     }

   }

   class BoxDemo

   {

     public static void main ( String ary[ ] )

     {

       Box x;

       Box b1 =new Box( );

       WoddenBox wb=new WoddenBox( );

       SteelBox s1=new SteelBox( );

       LargeWoddenBox p1=new LargeWoddenBox( );

       b1.info( );

       wb.info( );

       s1.info( );

       p1.info( );

     }

   }