Java 中的活动线程组是什么？
What is active thread group in Java?
有方法 java.lang.ThreadGroup.activeGroupCount() returns 估计线程组中活动组的数量。响应this question，活动线程被定义。但是活跃线程组是什么意思呢？
在Java中有一个围绕一组线程的组抽象，因此更容易管理一组线程。参见例如Java: Thread Group
Every Java thread is a member of a thread group. Thread groups provide a mechanism for collecting multiple threads into a single object and manipulating those threads all at once, rather than individually.
For example, you can start or suspend all the threads within a group with a single method call. Java thread groups are implemented by the ThreadGroup(in the API reference documentation) class in the java.lang package.
如您所述，ThreadGroup::activeGroupCount 的 javadoc 中出现了术语 "active thread group"。
活动线程组是 ThreadGroup 至少包含一个活动线程。
活动线程是 Thread::isAlive returns true 的线程。也就是说已经开始了，还没有结束。
请注意，线程组仅适用于调试；参见 What is the benefit of ThreadGroup in java over creating separate threads?. For example, the enumerate method has this javadoc 注意事项：
"Due to the inherent race condition in this method, it is recommended
that the method only be used for debugging and monitoring purposes."
这也适用于 "count" 方法。
有方法 java.lang.ThreadGroup.activeGroupCount() returns 估计线程组中活动组的数量。响应this question，活动线程被定义。但是活跃线程组是什么意思呢？
在Java中有一个围绕一组线程的组抽象，因此更容易管理一组线程。参见例如Java: Thread Group
Every Java thread is a member of a thread group. Thread groups provide a mechanism for collecting multiple threads into a single object and manipulating those threads all at once, rather than individually.
For example, you can start or suspend all the threads within a group with a single method call. Java thread groups are implemented by the ThreadGroup(in the API reference documentation) class in the java.lang package.
如您所述，ThreadGroup::activeGroupCount 的 javadoc 中出现了术语 "active thread group"。
活动线程组是 ThreadGroup 至少包含一个活动线程。
活动线程是 Thread::isAlive returns true 的线程。也就是说已经开始了，还没有结束。
请注意，线程组仅适用于调试；参见 What is the benefit of ThreadGroup in java over creating separate threads?. For example, the enumerate method has this javadoc 注意事项：
"Due to the inherent race condition in this method, it is recommended that the method only be used for debugging and monitoring purposes."
这也适用于 "count" 方法。