虚引用

package com.wb.demo.util;

import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.util.LinkedList;
import java.util.List;

public class PhantoReference {
     //容器
    final static List<Object> list = new LinkedList<>();
    //
    final static ReferenceQueue<TTT> queue = new ReferenceQueue<>();

    public static void main(String[] args) {
        PhantomReference<TTT> phantomReference = new PhantomReference(new TTT(), queue);
        new Thread(() -> {
            while (true) {
//一直添加数据
                list.add(new Byte[1024 * 1024]);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                    Thread.currentThread().interrupt();
                }
                System.out.println(phantomReference.get());
            }
        }).start();

        new Thread(() -> {
            while (true) {
//被回收时，放入queue
                Reference poll = queue.poll();
                if (poll != null) {
                    System.out.println("---------  虚引用对象被jvm回收了     --------------" + poll);
                }
            }
        }).start();
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}