coding: 写一个线程死锁demo

题

写一个线程死锁demo

解

思路

创建两个资源变量； 创建两个线程；

线程1先获取并锁定资源1，休眠一段时间再获取并锁资源2；

线程2先获取并锁定资源2，休眠一段时间再获取并锁资源1；

由于资源1已经被线程1锁定，线程2无法获取； 由于资源2已经被线程2锁定，线程1无法获取； 造成死锁。

代码

public class DeadClockDemo {
    private static final Object val1=1;
    private static final Object val2=2;
    private static class Thread1 extends Thread{
        @Override
        public void run(){
            synchronized (val1){    //读取并锁val1
                try {
                    System.out.println(Thread.currentThread()+" get val1");
                    System.out.println(Thread.currentThread()+" is waiting val2");
                    Thread.sleep(5000);     //线程休眠
                    synchronized (val2){    //读取并锁val2
                        System.out.println(Thread.currentThread()+" get val2");
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    private static class Thread2 extends Thread{
        @Override
        public void run(){
            synchronized (val2){    //读取并锁val2
                try {
                    System.out.println(Thread.currentThread()+" get val2");
                    System.out.println(Thread.currentThread()+" is waiting val1");
                    Thread.sleep(5000);
                    synchronized (val1){     //读取并锁 val1
                        System.out.println(Thread.currentThread()+" get val1");
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
        //启动线程
        new Thread1().start();
        new Thread2().start();
    }
}