synchronized(lock){
  lock.wait();   //進入waiting狀態(tài)，釋放鎖
}

synchronized(lock){
  lock.notifyAll();   //，喚醒所有線程，使所有在waiting狀態(tài)的線程進入blocked狀態(tài)，進入entry List隊列和其他線程一起競爭鎖
}

public final void join() throws InterruptedException {
    join(0);
  }


public final synchronized void join(long millis)
  throws InterruptedException {
    long base = System.currentTimeMillis();
    long now = 0;

    if (millis < 0) {
      throw new IllegalArgumentException("timeout value is negative");//判斷是否超時
    }

    if (millis == 0) {
      while (isAlive()) {   //判斷線程是否活著，如果
        wait(0);
      }
    } else {
      while (isAlive()) {
        long delay = millis - now;
        if (delay <= 0) {
          break;
        }
        wait(delay);
        now = System.currentTimeMillis() - base;
      }
    }
  }

park(t){
if(t.ounter == 0)
t.wait;
else if (t.counter == 1)
counter = 0;
}

unpark(t){
if(t.counter == 1)

}
e;se if(t.counter == 0){
t.counter = 0;
喚醒t線程
}