[Concurrent programming] --- java daemon thread Profile

Source Address: https://github.com/nieandsun/concurrent-study.git

1 Introduction to the concept daemon thread

Daemon (daemon) thread is a type of thread support, it is primarily used as back-end scheduling and supportive work program. When non-Daemon thread does not exist in a Java virtual machine, Java Virtual Machine exits.
By calling Thread.setDaemon (true) Daemon thread to thread. We generally do not have access, such as garbage collection thread is Daemon thread.

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2 daemon thread sample code and Notes

• Test code:

package com.nrsc.ch1.base;

/**
 * 类说明：守护线程的使用
 */
public class DaemonThread {
    private static class UseThread extends Thread {
        @Override
        public void run() {
            try {
                while (!isInterrupted()) {
                    System.out.println(Thread.currentThread().getName()
                            + " I am extends Thread.");
                }
                System.out.println(Thread.currentThread().getName()
                        + " interrupt flag is " + isInterrupted());
            } finally {
                //守护线程中finally不一定起作用
                System.out.println(" .............finally");
            }
        }
    }

    public static void main(String[] args) throws InterruptedException {
        UseThread useThread = new UseThread();
        useThread.setDaemon(true);
        useThread.start();
        Thread.sleep(1);
        //useThread.interrupt();
    }
}

• When useThread non-daemon threads

• useThread is daemon thread:

We can see by the above tests

• The main thread ends, a daemon thread will come to an end - "non-daemon threads do not
• finally there is the guardian of the thread may not be performed