在使用CountDownLatch的时候报Exception in thread “Thread-0” java.lang.IllegalMonitorStateException异常
public class Gh {
private static int a = 0, b = 0;
private static int x = 0,y = 0;

public static void main(String[] args) throws InterruptedException {
    CountDownLatch latch = new CountDownLatch(1);
    Thread thread1 = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                latch.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            a = 1;
            x = b;
        }
    });

    Thread thread2 = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                latch.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            b = 1;
            y = a;
        }
    });

    thread1.start();
    thread2.start();
    latch.countDown();
    thread1.join();
    thread2.join();
    System.out.println(x+","+y);
}