java stop方法爲什麼不能用？

一方面stop線程非常粗暴，除非可能執行finally代碼塊以及釋放synchronized外，線程將直接被終止，非常粗暴，此外如果線程持有JUC的互斥鎖，還可能導致鎖來不及釋放，造成其他線程永遠等待的局面。

JUC是Lock不是自動釋放的，需要主動釋放並且要在finally代碼塊中釋放，實際上是stop一個線程並不會跳過finally代碼塊，但是如果還沒有執行try代碼塊就被stop了，那就不會執行finally代碼塊，這會造成"鎖"永遠不會釋放，而其他線程永遠無法獲取鎖的尷尬局面了。

測試代碼:

public class TestStopLockThread {
  private static Lock lock = new ReentrantLock();
  public static void main(String[] args) throws Exception {
    Thread thread1 = new MyThread();
    thread1.setName("thread1");
    thread1.start();
    sleep(3);
    Thread thread2 = new MyThread();
    thread2.setName("thread2");
    thread2.start();
    //直接殺死
    System.out.println(nowTime() + " stop thread1");
    thread1.stop();
    //等待線程終止
    thread1.join();
    thread2.join();
  }
  private static class MyThread extends Thread{
    @Override
    public void run() {
      fun1();
    }
  }
  private static void fun1(){
    System.out.println(nowTime() + Thread.currentThread().getName() + " start");
    lock.lock();
    //假設恰好在此刻被stop了,下面通過睡眠來模擬這種特殊情況
    sleep(10);
    try {
      sleep(30);
      System.out.println(nowTime() + Thread.currentThread().getName() + " end");
    }finally {
      System.out.println(nowTime() + Thread.currentThread().getName() + " finally執行");
      lock.unlock();
    }
  }
}

過了很久很久，控制檯輸出如下:

2020/07/07 22:44:37 thread1 start
2020/07/07 22:44:40 stop thread1
2020/07/07 22:44:40 thread2 start