java实现死锁

死锁案例分析

最新推荐文章于 2025-03-27 00:15:00 发布

原创最新推荐文章于 2025-03-27 00:15:00 发布 · 96 阅读

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本文通过一个具体的Java程序示例，展示了如何在多线程环境下产生死锁现象。代码中两个线程分别尝试获取不同的对象锁，在成功获取一个锁之后等待另一个锁，导致两者都无法继续执行，形成死锁。


public class DeadLock extends Thread {
    private int flag = 1;
    // 一定要写成static的，否则形不成死锁
    private static Object o1 = new Object();
    private static Object o2 = new Object();

    @Override
    public void run() {
        if (1 == flag) {
            synchronized (o1) {
                System.out.println("waiting for o2...");
                try {
                    Thread.sleep(5000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (o2) {
                    System.out.println("o1 processing over");
                }
            }
        }

        if (0 == flag) {
            synchronized (o2) {
                System.out.println("waiting for o1...");
                try {
                    Thread.sleep(5000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (o1) {
                    System.out.println("o2 processing over");
                }
            }
        }
    }

    public static void main(String[] args) throws InterruptedException {
        DeadLock deadLock1 = new DeadLock();
        DeadLock deadLock2 = new DeadLock();

        deadLock1.flag = 1;
        deadLock2.flag = 0;

        deadLock1.start();
        Thread.sleep(50);
        deadLock2.start();
    }
}