public class Downcasting2
{
   public static void main(String[] args)
   {
      BankAccount x;             // x is a Base class variable

      CheckingAccount y;         // y and z are Derived class variables
      CheckingAccount z;


      /* -------------------------------------------------------
         Remember that:
            A derived class may have MORE variables/methods 
            than the base class !
         ------------------------------------------------------- */

      /* --------------------------------
         An ILLEGAL downcasting scenario
         -------------------------------- */
      x = new BankAccount(343, "John", 2000.0);

                                // x references a BankAccount object

      z = (CheckingAccount) x;  // Downcasting, NOT allowed because:
                                //    x references a BankAccount object
                                //    z is a CheckingAccount reference var.
                                //
                                // A CheckingAccount object has 
                                // MORE variables/methods than 
                                // a BankAccount object.
                                // Some operations are NOT possible !
   }
}