b.java

java 教程源码

//c5:B.java
//author:ZhangHongbin 
//This program is protected by copyright laws.
//Upcasting of class.  
class A
{
	void func( A a)
	{
		System.out.println(" func");

	}
}
class B extends A
{
	public static void main(String[] args)
	{
		B b=new B();
		A a=new A();
		b.func(a);
		System.out.println(" Begin upcasting");
		b.func(b); // Upcasting
	}
}