public class TestWait {

    public static void main(String[] args) throws InterruptedException {

        Thread t = new MyThread("t1");

        synchronized (t){ //main线程持有t对象的锁

            System.err.println(Thread.currentThread().getName() + "... start");

            t.start(); //t被启动后,t执行run里面的方法会阻塞,因为当前线程main持有t对象的锁

            System.err.println(Thread.currentThread().getName() + "... in wait...");

            t.wait(2);//当前main线程进入阻塞(等待)状态,并且线程main释放t的锁,然后main等待notify后重新去竞争t的锁然后继续执行.

            //t对象的锁被释放后，线程t执行run方法的sync会获取到锁然后得到执行,执行完后notify该对象t上面等待的线程main(本例子只有main)

            //主线程main被唤醒，然后重新竞争t对象的锁,得到锁后，继续执行end.

            System.err.println(Thread.currentThread().getName() + "... end");

        }

    }

    static class MyThread  extends Thread {

        public MyThread(String name) {

            super(name);

        }

        @Override

        public void run() {

            synchronized (this){

                for (int i = 0; i < 5; i++) {

                    try {

                        Thread.sleep(1000);

                    } catch (InterruptedException e) {

                        e.printStackTrace();

                    }

                    System.err.println(Thread.currentThread().getName() + "_exec.."+i);

                }

                System.err.println(Thread.currentThread().getName() + "_ notify....");

                notify();//执行完后notify该对象t上面等待的线程,比如主线程

            }

        }

    }

}