Java线程死锁

骑猪看日落 2022-09-26 02:18 251阅读 0赞

/\*  
\* 【线程死锁】  
\* 原因：两个线程相互等待被对方锁定的资源  
\*/

代码模拟：

public class DeadLock { 
        public static void main(String[] args) {
            Object obj = new Object();
            Object obj1 = new Object();
            DeadLockThread1 D1 = new DeadLockThread1(obj, obj1);
            DeadLockThread2 D2 = new DeadLockThread2(obj, obj1);
            new Thread(D1,"线程1").start();
            new Thread(D2,"线程2").start();
        }
    }
    
    class DeadLockThread1 implements Runnable { 
        private Object obj;
        private Object obj1;
    
        public DeadLockThread1(Object obj, Object obj1) {
            this.obj = obj;
            this.obj1 = obj1;
        }
    
        @Override
        public void run() {
            synchronized (obj) {     //DeadLockThread1锁定obj对象
                try {
                    Thread.sleep(1000);
                    synchronized (obj1) {  //等待锁定obj1对象，obj对象已被DeadLockThread2锁定
                        obj1.getClass();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    
    class DeadLockThread2 implements Runnable { 
        private Object obj;
        private Object obj1;
    
        public DeadLockThread2(Object obj, Object obj1) {
            this.obj = obj;
            this.obj1 = obj1;
        }
    
        @Override
        public void run() {
            synchronized (obj1) {     //DeadLockThread2锁定obj2对象
                try {
                    Thread.sleep(1000);
                    synchronized (obj) {  //等待锁定obj对象，obj对象已被DeadLockThread1锁定
                        obj.getClass();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

查看方式：  
1、【cmd】下输入【jconsole】  
![这里写图片描述][20160916214422435]

2、选择测试线程并点击右下角【连接】，左上角选择【线程】，左下角选择【检测死锁】  
![这里写图片描述][20160916214658315]

[20160916214422435]: /images/20220717/c3a153c186f3495fad3699a7fc3b51e6.png
[20160916214658315]: /images/20220717/1054dded37ce4912be1e0588ad272092.png