The current thread must own this object's monitor.

这是Object类中，wait方法的注释中的一段话，

这句话的意思是：wait()会释放对象的锁，所以调用wait的条件是一定要拥有对象的锁，所以wait方法应该放在synchronize里面，如下

package com.lin.thread;

public class ThreadWait {
    private Object lock;

    public ThreadWait(Object lock) {
        this.lock = lock;
    }


    public void testWait(){
        synchronized (lock) {
            System.out.println("start wait...");
            try {
                lock.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("end wait ...");
        }
    }
}