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[A] 添加弱引用实例

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	`1`	`+package com.learnjava.reference;`
	`2`	`+`
	`3`	`+import java.lang.ref.Reference;`
	`4`	`+import java.lang.ref.ReferenceQueue;`
	`5`	`+import java.lang.ref.WeakReference;`
	`6`	`+`
	`7`	`+public class WeakReferenceTest {`
	`8`	`+ public static void main(String[] args) throws Exception {`
	`9`	`+ test02();`
	`10`	`+ }`
	`11`	`+`
	`12`	`+ private static void test02() throws InterruptedException {`
	`13`	`+ ReferenceQueue refQueue = new ReferenceQueue();`
	`14`	`+`
	`15`	`+ // 10 mb`
	`16`	`+ byte[] buffer = new byte[1024 * 1024 * 10];`
	`17`	`+ WeakReference weakReference = new WeakReference(buffer, refQueue);`
	`18`	`+ // 失去强引用关联`
	`19`	`+ buffer = null;`
	`20`	`+`
	`21`	`+ Reference ref0 = refQueue.poll();`
	`22`	`+ System.out.println("gc 执行之前, refQueue中是否有数据?" + (ref0 != null ? "有" : "没有"));`
	`23`	`+ System.out.println("gc 执行之前, ref引用的对象:" + weakReference.get());`
	`24`	`+`
	`25`	`+ System.gc();`
	`26`	`+ // 确保gc程序执行`
	`27`	`+ Thread.sleep(1000);`
	`28`	`+`
	`29`	`+ System.out.println("gc 执行之前, ref引用的对象:" + weakReference.get());`
	`30`	`+`
	`31`	`+ Reference ref = refQueue.poll();`
	`32`	`+ System.out.println("referenceQueue 中获取的 ref与 weakReference中的是否一致?" + (ref == weakReference));`
	`33`	`+ }`
	`34`	`+}`

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