java object wait notify 学习

package com.study.controller;

public class TestObjectWait {
    public static void main(String[] args) {
        final Object lock = new Object();
        new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (lock) {
                    System.out.println(Thread.currentThread().getName() + "拿到锁了");
                    try {
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + "拿到信号");
                    System.out.println(Thread.currentThread().getName() + "释放锁");
                }
            }
        }, "线程1").start();
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    System.out.println(Thread.currentThread().getName() + "先不拿锁，sleep 3000");
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (lock) {
                    System.out.println(Thread.currentThread().getName() + "拿到锁了");
                    try {
                        System.out.println(Thread.currentThread().getName() + "拿到锁后，sleep 3000");
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + "发出信号");
                    lock.notifyAll();
                    try {
                        Thread.sleep(3000);
                        System.out.println(Thread.currentThread().getName() + "发出信后，sleep 3000");
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + "释放锁");
                }
            }
        }, "线程2").start();
        new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (lock) {
                    System.out.println(Thread.currentThread().getName() + "拿到锁了");
                    try {
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + "拿到信号");
                    System.out.println(Thread.currentThread().getName() + "释放锁");
                }
            }
        }, "线程3").start();
    }
}