package com.roocon.thread.t6;public class Demo3 {    private Object obj1 = new Object();    private Object obj2 = new Object();    public void a(){        synchronized (obj1){            try {                Thread.sleep(3000);            } catch (InterruptedException e) {                e.printStackTrace();            }            synchronized (obj2){                System.out.println("a");            }        }    }    public void b(){        synchronized (obj2){            try {                Thread.sleep(3000);            } catch (InterruptedException e) {                e.printStackTrace();            }            synchronized (obj1){                System.out.println("b");            }        }    }    public static void main(String[] args) {        Demo3 demo3 = new Demo3();        new Thread(new Runnable() {            @Override            public void run() {                demo3.a();            }        }).start();        new Thread(new Runnable() {            @Override            public void run() {                demo3.b();            }        }).start();    }}

运行结果：

控制台一直在运行，但是无任何输出。

 

通过命令检测是否真的发生了死锁：

点击线程，检测死锁：