/*
  An example from Java: A beginners's guide by Herbert Schildt that
  illustrates the the strongly typed nature of Java.  A reference for one
  type of object cannot normally refer to another type of object except
  whne a reference of a superclass is referred to an object that's a
  subclass.
  v1 - won't compile.
  v2 - uses inheritance and will compile
*/
public class Yv1
{
    private int a;

    public Yv1(int i)
    {
	a = i;
    }
}