Java守护线程

(守护进程)

Java使用用户线程和守护进程线程概念。

JVM流

1. If there are no `user treads` JVM starts terminating the program
2. JVM terminates all `daemon threads` automatically without waiting when they are done
3. JVM is shutdown

正如你所看到的，守护线程是用户线程的服务线程。

守护线程是低优先级线程。 线程从父线程继承它的属性。要从外部设置它，你可以在启动它之前使用setDaemon()方法或通过isDaemon()检查它

守护线程是在程序完成但线程仍在运行时不阻止JVM退出的线程。守护进程线程的一个例子是垃圾收集。

您可以使用setDaemon(boolean)方法在线程启动之前更改线程守护进程属性。

Daemon threads are those threads which provide general services for user threads (Example : clean up services - garbage collector) Daemon threads are running all the time until kill by the JVM Daemon Threads are treated differently than User Thread when JVM terminates , finally blocks are not called JVM just exits JVM doesn't terminates unless all the user threads terminate. JVM terminates if all user threads are dies JVM doesn't wait for any daemon thread to finish before existing and finally blocks are not called If all user threads dies JVM kills all the daemon threads before stops When all user threads have terminated, daemon threads can also be terminated and the main program terminates setDaemon() method must be called before the thread's start() method is invoked Once a thread has started executing its daemon status cannot be changed To determine if a thread is a daemon thread, use the accessor method isDaemon()

守护线程就像一个普通的线程，除了JVM只会在其他非守护线程不存在时关闭。守护进程线程通常用于为应用程序执行服务。

传统上，UNIX中的守护进程是那些不断在后台运行的进程，就像Windows中的服务一样。

Java中的守护线程是不阻止JVM退出的线程。特别是当只剩下守护线程时，JVM将退出。您可以通过调用线程上的setDaemon()方法来创建一个。

读取Daemon线程。

守护线程是在进程的其他非守护线程仍在运行时在后台运行的线程。因此，当所有非守护进程线程完成时，守护进程线程将终止。非守护进程线程的一个例子是运行Main的线程。 通过在线程启动之前调用setDaemon()方法，将线程设置为守护进程

更多参考:Java中的守护进程线程