Java 线程中断标志被清除

Question

我正在尝试java中的中断，并观察到，如果我中断一个线程并且当线程状态从RUNNABLE更改为TERMINATED时不重置它的中断状态，则中断变量将被重置(interrupted变为false)

Main.java

public class Main {

public static void main(String[] args) {

    try {

        t1 t1 = new t1();
        t1.start();

        Thread.sleep(10);
        t1.interrupt();
        System.out.println("t1.isInterrupted: " + t1.isInterrupted() + " t1.state: " + t1.getState());
        Thread.sleep(20);
        System.out.println("t1.isInterrupted: " + t1.isInterrupted() + " t1.state: " + t1.getState());

    } catch (Exception exc) {
        System.out.println("Exception: " + exc);
    }

}

}

t1.java

public class t1 extends Thread {

@Override
public void run() {

    while (!Thread.currentThread().isInterrupted()) {
        System.out.println("Processing");
    }

    System.out.println("Execution completed - interrupt status: " + Thread.currentThread().isInterrupted());
}

}

Main.java 的输出(Centos 7 64 位，Java 1.8.0_66-b17)

• 处理
  加工
  加工
  t1.isInterrupted: true t1.state: RUNNABLE
  执行完成 - 中断状态:true
  t1.isInterrupted: false t1.state: 已终止

我的问题是谁或什么将此标志设置回 false，为什么？ Thread 类有一个私有(private)退出方法，它将一些内部变量设置为 null，但我找不到任何重置中断标志的东西。如果有人能阐明这个问题，我将不胜感激......

PS:这里是GIST的链接

Answer 1

My question is who or what sets this flag back to false and why ?

这是线程终止时的已知行为。因为它不再运行，所以中断状态为假。中断状态在线程终止之前为 true，但在线程完成后设置为 false。

引用Thread.isInterrupted() javadocs :

A thread interruption ignored because a thread was not alive at the time of the interrupt will be reflected by this method returning false.