需要了解以下代码的场景

Question

我有以下代码..

import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

public class daemonTest {

    public static void main(String... a) throws Exception {
        ExecutorService service = Executors
                .newSingleThreadExecutor(new ThreadFactory() { // anonmyous class start
                    public Thread newThread(Runnable r) {
                        Thread two = new Thread(r, "two");
                        two.setDaemon(true);
                        System.out.println("two --->" + two.isDaemon());
                        return two;
                    }
                });
        for (int i = 0; i < 10; i++)
            service.submit(new Runnable() {
                @Override
                public void run() {
                    System.out.println("[" + Thread.currentThread().getName()
                            + "] - Hello World.");
                    Thread.yield();
                }
            });
        service.shutdown();
    }
}

结果的输出是……

two --->true
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.
[two] - Hello World.

请告知上面这段代码在做什么..因为我想要实现的是将一个线程设置为守护进程，然后该守护线程将为非守护线程提供服务！！

Answer 1

请告知上面的代码在做什么..

这是你的代码：

        service.submit(new Runnable() {
            @Override
            public void run() {
                System.out.println("[" + Thread.currentThread().getName()
                        + "] - Hello World.");
                Thread.yield();
            }
        });

您正在提交 10 个工作，它们执行 println，一个无关紧要的 yield()，然后立即提交。他们不等待任何线程。如果你需要它，那么你需要一个 two.join() 在你的 runnable 中的某个地方。