请稍等 ...

谁先进入等待池，notify就先唤醒谁，并不是随机唤醒？？？

翔仔老师你好！
这是我的代码：
/**
*

notify与notifyAll的区别

*/
public class NotifyDemo {
private boolean isGo = false;

public static void main(String[] args) {
	NotifyDemo notifyDemo = new NotifyDemo();
	Runnable waitRunn = new Runnable() {

		@Override
		public void run() {
			notifyDemo.waitTask();
			System.out.println(Thread.currentThread().getName() + "，执行完毕");
		}
	};
	Runnable notifyRunn = new Runnable() {

		@Override
		public void run() {
			notifyDemo.notifyTask();
		}
	};
	Thread t1 = new Thread(waitRunn, "线程1");
	Thread t2 = new Thread(waitRunn, "线程2");
	Thread t3 = new Thread(waitRunn, "线程3");
	Thread t4 = new Thread(waitRunn, "线程4");
	Thread t5 = new Thread(waitRunn, "线程5");
	Thread t6 = new Thread(waitRunn, "线程6");

	Thread tNotify = new Thread(notifyRunn, "线程notify");

	t1.start();
	t2.start();
	t3.start();
	t4.start();
	t5.start();
	t6.start();
	
	try {
		Thread.sleep(2000);
	} catch (InterruptedException e) {
		e.printStackTrace();
	}
	tNotify.start();
}

private synchronized void waitTask() {
	while (!isGo) {
		try {
			System.out.println(Thread.currentThread().getName() + "，进入等待池");
			wait();
			System.out.println(Thread.currentThread().getName() + "，被唤醒");
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

private synchronized void notifyTask() {
	while (!isGo) {
		isGo = true;
		 System.out.println("随机唤醒一个线程并让它进入锁池");
		 notify();
		// System.out.println("唤醒全部线程并让它们进入锁池");
		// notifyAll();
	}
}

}
我执行了以上代码几十次，每次先进入等待池的线程，都会被notify唤醒，而没有出现随机唤醒的情况。这是什么原因导致的呢？
console打印结果：
图片描述