testreference.java

疯狂Java讲义_源码(含Java设计模式CHM

import java.lang.ref.*;
/**
 * Description:
 * <br/>Copyright (C), 2005-2008, 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
 */
public class TestReference
{
	public static void main(String[] args) throws Exception
	{
		//创建一个字符串对象
		String str = new String("Struts2权威指南");
		//创建一个弱引用，让此弱引用引用到"Struts2权威指南"字符串
		WeakReference wr = new WeakReference(str);
		//切断str引用和"Struts2权威指南"字符串之间的引用
		str = null;
		//取出弱引用所引用的对象
		System.out.println(wr.get());
		//强制垃圾回收
		System.gc();
		System.runFinalization();
		//再次取出弱引用所引用的对象
		System.out.println(wr.get());
	}
}