[Java concurrent programming learning] 2. Thread interruption

public class SleepInterrupt extends Object implements Runnable {
    @Override
    public void run() {
        System.out.println("in run() - enter normally");
        try {
            System.out.println("in run() - about to sleep for 20 seconds");
            Thread.sleep(20000);
            System.out.println("in run() - woke up");
        } catch (InterruptedException e) {
            System.out.println("in run() - interrupted while sleeping");
            /**
             * After processing the interrupt exception, return to the entry of the run() method,
             * If there is no return, the thread will not actually be interrupted, it will continue to print the following information
             */
            return;
        }
        System.out.println("in run() - leaving normally");
    }
}

public class InterruptDemo {
    public static void main(String[] args) {
        SleepInterrupt sleepInterrupt = new SleepInterrupt();
        Thread thread = new Thread(sleepInterrupt);
        thread.start();
        // The main thread sleeps for 2 seconds to ensure that the thread just started has a chance to execute for a while
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace ();
        }
        System.out.println("in main() - interrupting other thread");
        /**
         * When a thread is running, another thread can call the interrupt() method of the corresponding Thread object to interrupt it,
         * This method just sets a flag in the target thread, indicating that it has been interrupted, and returns immediately
         */
        thread.interrupt();
        System.out.println("in main() - leaving");
    }
}