没 bug ，先 unpark 的话，下次 park 会失效，应该是有个标志位，能抵消一次 park

```java
@Test
public void test() throws InterruptedException {


Thread thread = new Thread(() -> {
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
System.out.println("start park in thread 1");
LockSupport.park(Thread.currentThread());
System.out.println("start park in thread 2");
LockSupport.park(Thread.currentThread());
System.out.println("end park in thread");
});

thread.start();

TimeUnit.SECONDS.sleep(1);

System.out.println("start unpark in main");
LockSupport.unpark(thread);
LockSupport.unpark(thread);
System.out.println("end unpark in main");

TimeUnit.SECONDS.sleep(4);

LockSupport.unpark(thread);

TimeUnit.SECONDS.sleep(100);

}
```