模拟死锁

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：