调用wait方法报错，有前辈能指导下吗

Question

public class Test{
    public static Integer i=0;
    public static void main(String[] args) {

        Object o1=new Object();
        ReentrantLock lock=new ReentrantLock();

        Thread t1=new Thread(new Runnable() {

            @Override
            public  void run() {
                lock.lock();
                i++;
                try {
                    this.wait(2000l);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println(i);
                lock.unlock();
            }

        });

        Thread t2=new Thread(new Runnable() {
            @Override
            public  void run() {
                lock.lock();
                i++;
                System.out.println(i);
                lock.unlock();
            }
        });
        t1.start();

        try {
            Thread.sleep(10l);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        t2.start();
    }
}

报错如下

Exception in thread "Thread-0" java.lang.IllegalMonitorStateException
    at java.lang.Object.wait(Native Method)
    at com.suning.ctmodp.Controller.Test$1.run(Test.java:19)
    at java.lang.Thread.run(Thread.java:748)

 

调用wait方法报错了，我觉得调用wait得时候t1是拿到自己得对象所得不知道为啥报这个，其实我一开始写的是lock.wait(),我就想看下wait是不是释放锁了，之前用sleep结果正确没有释放锁，难道lock之后不能调用wait方法吗

Answer 1

import java.util.concurrent.locks.ReentrantLock;

public class Test{
    public static Integer i=0;
    public static void main(String[] args) {

        Object o1=new Object();
        ReentrantLock lock=new ReentrantLock();

        Thread t1=new Thread(new Runnable() {

            @Override
            public  void run() {
            	synchronized (this) {
                lock.lock();
                i++;
                try {
                    this.wait(2000l);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println(i);
                lock.unlock();
            }

        }
    });

        Thread t2=new Thread(new Runnable() {
            @Override
            public  void run() {
                lock.lock();
                i++;
                System.out.println(i);
                lock.unlock();
            }
        });
        t1.start();

        try {
            Thread.sleep(10l);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        t2.start();
    }
}