Java主线程一直跑，子线程手动关闭并回收

如果主线程不需要一直循环，子线程池可以使用ThreadFactory setDaemon true 实现

主线程一直开启解决办法，上代码

@NoArgsConstructor
public class ThreadTest implements Runnable {

    PyList pyList;
    boolean flag = true;
    public ThreadTest(PyList pyList){
        this.pyList = pyList;
    }

    @Override
    public void run() {
        while(flag){
            pyList.add(Py.newFloat(24.69));
            System.out.println("ThreadTest");
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("结束");
    }

    public void shutdown(){
        this.flag = false;
    }
}

CustomizableThreadFactory threadFactory = new CustomizableThreadFactory("trend-iot-read-");
        ThreadPoolExecutor pool = new ThreadPoolExecutor(1, 2, 60L, TimeUnit.SECONDS, new LinkedBlockingQueue<>(1),threadFactory);

        PyObject[] data = {};
        PyList pyList = new PyList(data);

        ThreadTest threadTest = new ThreadTest(pyList);
        pool.execute(threadTest);


        for (int i = 0; i < 3; i++) {
            System.out.println(pyList.size()+"----------------------");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        threadTest.shutdown();
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(pool.getActiveCount());
        pool.shutdownNow();
        System.out.println(pool.isShutdown());

为什么主线程需要休眠，不休眠，子线程池中如果线程在休眠，挂起，就会报

java.lang.InterruptedException: sleep interrupted
    at java.lang.Thread.sleep(Native Method)
    at com.ars.team.tasks.config.ThreadTest.run(ThreadTest.java:26)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)