Java Program on Polymorphism

      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( );
     }
   }