public class HolidayDriver
{
   public static void main (String[] args)
   {
     Holiday [] a = new Holiday [3];
     a[0] = new Holiday();
     a[1] = new Christmas(); 
     a[2] = new Christmas();
       
// ilustrates polymorphism
// the celebrate method depends on the type of the object accessed by a[i]
     for (int i = 0; i<a.length; i++)
      {   
	      a[i].celebrate();
      }
      
     Holiday h, h1;
     Christmas c, c1;
     
     h1 = new Holiday();
     h1.celebrate();

     c1 = new Christmas();
     c1.celebrate();
     
// point to derived class object using reference to base class object
     h = new Christmas();
     h.celebrate();
       // ((Christmas)h).snow();
     
     //c = (Christmas)h1;
     //c.celebrate();
     
   }
}

     
public class Holiday
{
   public void celebrate()
   { 
     System.out.println ("This is a holiday!");
   }
   
   public void get_ready() 
   { 
	   System.out.println ("Get ready!");
   }
}


public class Christmas extends Holiday
{
   public void celebrate()
   { 
     System.out.println ("This is a white Christmas!");
   }
    
   public void snow()
   { 
     System.out.println ("It is snowing!");
   }

}