1.有两个对象锁A1、A2
2.两个线程t1、t2
3.t1的执行顺序是A1-->A2， t2的执行顺序是A2-->A1
4.出现状态 t1持有 A1 锁，等待 A2 锁； t2 持有 A2 锁，等待 A1 锁
5.出现死锁
检查死锁方法：使用jps查看线程pid，用jstack pid查看线程运行情况
DeadLock
package com.dwz.concurrency.chapter8; public class DeadLock { private OtherService otherService; private final Object LOCK = new Object(); public DeadLock(OtherService otherService) { this.otherService = otherService; } public void m1() { synchronized(LOCK) { System.out.println("m1--" + Thread.currentThread()); otherService.s1(); } } public void m2() { synchronized(LOCK) { System.out.println("m2--" + Thread.currentThread()); } } }
OtherService
package com.dwz.concurrency.chapter8; public class OtherService { private DeadLock deadLock; private final Object LOCK = new Object(); public void setDeadLock(DeadLock deadLock) { this.deadLock = deadLock; } public void s1() { synchronized (LOCK) { System.out.println("s1========" + Thread.currentThread()); } } public void s2() { synchronized (LOCK) { System.out.println("s2========" + Thread.currentThread()); deadLock.m2(); } } }
package com.dwz.concurrency.chapter8; public class DeadLockTest { public static void main(String[] args) { OtherService otherService = new OtherService(); DeadLock deadLock = new DeadLock(otherService); otherService.setDeadLock(deadLock); new Thread() { @Override public void run() { while(true) { deadLock.m1(); } } }.start(); new Thread() { @Override public void run() { while(true) { otherService.s2(); } } }.start(); } }
结果：没有异常信息，程序阻塞
原文：https://www.cnblogs.com/zheaven/p/12059807.html