System.out.println(((Parent)d).tag);

/**
 * Description:
 * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> 
 * <br/>Copyright (C), 2001-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
class Parent
{
	public String tag = "疯狂Java讲义";
}
class Derived extends Parent
{
	//定义一个私有的tag实例变量来隐藏父类的tag实例变量
	//private
	String tag = "轻量级Java EE企业应用实战";
}
public class HideTest
{
	public static void main(String[] args)
	{
		Derived d = new Derived();
		//程序不可访问d的私有变量:tag，所以下面语句引起编译错误
		System.out.println(d.tag);
		//将d变量显式地向上转型为Parent后，即可访问tag实例变量，
		//程序将输出："疯狂Java讲义"
		System.out.println(((Parent)d).tag);
	}
}
/*
轻量级Java EE企业应用实战
疯狂Java讲义
请按任意键继续. . .
*/