The Need for Worker Threads in a GUI Setting

	Chapter 10 - Thread Groups
	Java Thread Programming
	Paul Hyde

Copyright 1999 Sams Publishing

---

Using getParent()

If you need to know which thread group a particular thread group belongs to, you can use the getParent() method on ThreadGroup . Suppose at some time in the past, this code was executed:

ThreadGroup groupD = new ThreadGroup(groupC, groupD);

Then, later in the application, the following code is used:

ThreadGroup parentOfGroupD = groupD.getParent();

The reference returned and stored in parentOfGroupD refers to the same ThreadGroup instance as groupC does.

If getParent() is invoked on the root thread group, null is returned. In the VM, only one instance of ThreadGroup does not have a parent group, and that is the root group.

Toc