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This article mainly explains "the principle and use of ThreadGroup in Java". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "the principle and usage of ThreadGroup in Java".

1. Introduction

The Thread class has several constructors, one of which is as follows:

Public Thread (ThreadGroup group, String name) {init (group, null, name, 0);}

Pass in a ThreadGroup parameter that represents the thread group to which the current thread belongs. The above init in the source code is finally implemented as follows:

Private void init (ThreadGroup g, Runnable target, String name, long stackSize, AccessControlContext acc, boolean inheritThreadLocals) {. If (g = = null) {g = parent.getThreadGroup ();}}

If this thread group is not set, the thread group of the created thread is the thread group of its parent thread, that is, the current thread. If the current thread is a main thread and the group name of the main thread is also main, then the group of the new thread created in the main method is also main. This article will learn about the ThreadGroup class.

two。 Create ThreadGroup

Threads are called father and son, and thread groups are also called father and son.

The constructors of the ThreadGroup class are:

Public ThreadGroup (ThreadGroup parent, String name); public ThreadGroup (String name) {this (Thread.currentThread (). GetThreadGroup (), name);}

The constructor can specify the parent thread group of the currently created thread group, or, if not specified, the thread group of the current thread as the parent thread group of the newly created thread group.

Here is a demo for verification, and the result is printed as true.

Public static void main (String [] args) throws Exception {ThreadGroup threadGroup = Thread.currentThread (). GetThreadGroup (); ThreadGroup threadGroup1 = new ThreadGroup ("threadGroup1"); System.out.println (threadGroup1.getParent () = = threadGroup);} 2. ThreadGroup replication

Multiple threads and sub-thread groups can be added to a thread group, and they can be copied using their replication methods:

Public int enumerate (Thread list []); public int enumerate (Thread list [], boolean recurse)

The parameter recurse is true, which means that threads in all subthread groups are also copied into the array recursively. If this parameter is not available, the default is true.

In addition to copying threads in a thread group, you can also copy sub-thread groups in a thread group:

Public int enumerate (ThreadGroup list []); public int enumerate (ThreadGroup list [], boolean recurse)

Recurse also means whether to do recursion and copy.

3. Summary

Thread groups are not used to manage threads, but are organized for threads.

At this point, I believe you have a deeper understanding of "the principle and use of ThreadGroup in Java". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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