Java并发编程中的死锁实例分析

原创阳光穿透心脏的1/2处 2024-09-23 00:01 75阅读 0赞

死锁是Java并发编程中常见的问题，它发生在两个或更多的线程相互等待对方释放资源时，这种状态无法自行打破，即形成了"死锁"。

以下是一个简单的死锁实例：

```java
public class DeadLockExample {
    private Object lock1 = new Object();
    private Object lock2 = new Object();

public void thread1() {
        synchronized (lock1) {
            System.out.println("Thread 1 acquired lock1");
            // 执行耗时操作
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

System.out.println("Thread 1 released lock1");
            // 获取锁2，可能会造成死锁
            synchronized (lock2) {
                System.out.println("Thread 1 acquired lock2");
                // 执行耗时操作
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

System.out.println("Thread 1 released lock2");
            }
        }
    }

public void thread2() {
        synchronized (lock2) {
            System.out.println("Thread 2 acquired lock2");
            // 执行耗时操作
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

System.out.println("Thread 2 released lock2");
            // 获取锁1，可能会造成死锁
            synchronized (lock1) {
                System.out.println("Thread 2 acquired lock1");
                // 执行耗时操作
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

System.out.println("Thread 2 released lock1");
            }
        }
    }

public static void main(String[] args) {
        DeadLockExample example = new DeadLockExample();
        Thread thread1 = new Thread(example::thread1));
        Thread thread2 = new Thread(example::thread2));

thread1.start();
        thread2.start();
    }
}
```

在这个例子中，线程1先获取到`lock1`，然后尝试获取`lock2`。但是由于线程2已经持有`lock2`，所以线程1无法获取到，形成了死锁。