Java 引用

参考博文：

https://droidyue.com/blog/2014/10/12/understanding-weakreference-in-java/

http://puretech.iteye.com/blog/2008663

测试TestA

package prodconsumer;

public class TestA {
	int a;

	public int getA() {
		return a;
	}

	public void setA(int a) {
		this.a = a;
	}
	

}

package test;

import java.lang.ref.WeakReference;

import prodconsumer.TestA;

public class TestFinal {
	
 	public static void main(String[] args) {
 		TestA abc=new TestA();
 		WeakReference<TestA> weakWidget = new WeakReference<TestA>(abc);
		System.out.println(weakWidget.get());
		int i=0; 
		 while(true){  
	            if(weakWidget.get()!=null){  
	                i++;  
	                System.out.println("Object is alive for "+i+" loops - "+weakWidget);  
	            }else{  
	                System.out.println("Object has been collected.");  
	                break;  
	            }  
	        }  
	}

}

运行一段时间后 car object 即被回收了。

弱引用或者软引用之类的有个好处，就是用于做cache.