Java并发编程中死锁问题实例

原创旧城等待， 2024-09-11 21:51 103阅读 0赞

在Java并发编程中，死锁是一种常见的问题。下面是一个简单的死锁实例：

```java
// 两个线程，分别代表A和B
class LockResource {
    Lock lock1 = new Lock();
    Lock lock2 = new Lock();

public void acquireLock1() {
        if (lock1.tryAcquire()) {
            System.out.println("Thread A acquired lock1.");
        } else {
            System.out.println("Thread A failed to acquire lock1.");
        }
    }

public void acquireLock2() {
        if (lock2.tryAcquire()) {
            System.out.println("Thread B acquired lock2.");
        } else {
            System.out.println("Thread B failed to acquire lock2.");
        }
    }
}

class ThreadA extends Thread {
    @Override
    public void run() {
        LockResource resource = new LockResource();
        try {
            // 对锁1进行两次获取，模拟死锁
            resource.acquireLock1();
            resource.acquireLock1();

System.out.println("Thread A acquired lock1 twice, but no deadlock detected.");
        } catch (Exception e) {
            System.out.println("Thread A failed to acquire locks: " + e.getMessage());
        }
    }
}

class ThreadB extends Thread {
    @Override
    public void run() {
        LockResource resource = new LockResource();
        try {
            // 对锁2进行两次获取，模拟死锁
            resource.acquireLock2();
            resource.acquireLock2();

System.out.println("Thread B acquired lock2 twice, but no deadlock detected.");
        } catch (Exception e) {
            System.out.println("Thread B failed to acquire locks: " + e.getMessage());
        }
    }
}

public class Main {
    public static void main(String[] args) {
        ThreadA threadA = new ThreadA();
        ThreadB threadB = new ThreadB();

// 启动两个线程
        threadA.start();
        threadB.start();
    }
}
```

在这个例子中，当ThreadA获取锁1后，如果ThreadB尝试获取锁2（而锁1尚未释放），就会出现死锁。然而，这个程序并没有引发真正的死锁，因为我在模拟死锁时故意省略了释放锁的步骤。在实际应用中，请确保按照正确的顺序释放锁。