package thread;
public class WaitAndNotify {
    public void testWait(Object lock){
        try{
            synchronized(lock){
                System.out.println("start wait........");
                lock.wait();
                System.out.println("end wait........");
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public void testNotify(Object lock){
        try{
            synchronized(lock){
                System.out.println("start Notify........");
                lock.notify();
                System.out.println("end Notify........");
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public static void main(String[] args)throws Exception {
        Object lock = "";
        WaitAndNotify test = new WaitAndNotify();
        new Thread(new Runnable() {
            @Override
            public void run() {
                test.testWait(lock);
            }
        }).start();
        new Thread().sleep(2000);
        new Thread(new Runnable() {
            @Override
            public void run() {
                test.testNotify(lock);
            }
        }).start();
    }
}

结果

start wait........
start Notify........
end Notify........
end wait........

wait等到,释放锁,notify唤醒线程,notifyAll唤醒所有线程