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<h3>
e99.
Listing All Running Threads</h3>
A thread exists in a thread group and a thread group can contain other
thread groups. This example visits all threads in all thread groups.
<pre>
// Find the root thread group
ThreadGroup root = Thread.currentThread().getThreadGroup().getParent();
while (root.getParent() != null) {
root = root.getParent();
}
// Visit each thread group
visit(root, 0);
// This method recursively visits all thread groups under `group'.
public static void visit(ThreadGroup group, int level) {
// Get threads in `group'
int numThreads = group.activeCount();
Thread[] threads = new Thread[numThreads*2];
numThreads = group.enumerate(threads, false);
// Enumerate each thread in `group'
for (int i=0; i<numThreads; i++) {
// Get thread
Thread thread = threads[i];
}
// Get thread subgroups of `group'
int numGroups = group.activeGroupCount();
ThreadGroup[] groups = new ThreadGroup[numGroups*2];
numGroups = group.enumerate(groups, false);
// Recursively visit each subgroup
for (int i=0; i<numGroups; i++) {
visit(groups[i], level+1);
}
}
</pre>
Here's an example of some thread groups that contain some threads:
<pre>
java.lang.ThreadGroup[name=system,maxpri=10]
Thread[Reference Handler,10,system]
Thread[Finalizer,8,system]
Thread[Signal Dispatcher,10,system]
Thread[CompileThread0,10,system]
java.lang.ThreadGroup[name=main,maxpri=10]
Thread[main,5,main]
Thread[Thread-1,5,main]
</pre>
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Related Examples
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e92. <a class="eglink" href="BasicThread.html?l=rel">
Creating a Thread
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e93. <a class="eglink" href="StopThread.html?l=rel">
Stopping a Thread
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e94. <a class="eglink" href="IfStopped.html?l=rel">
Determining When a Thread Has Finished
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e95. <a class="eglink" href="Sleep.html?l=rel">
Pausing the Current Thread
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e96. <a class="eglink" href="PauseThread.html?l=rel">
Pausing a Thread
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e97. <a class="eglink" href="IfLocked.html?l=rel">
Determining If the Current Thread Is Holding a Synchronized Lock
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e98. <a class="eglink" href="DaemonThread.html?l=rel">
Allowing an Application with Live Threads to Exit
</a>
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e100. <a class="eglink" href="TLocal.html?l=rel">
Using a Thread-local Variable
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e101. <a class="eglink" href="GetStack.html?l=rel">
Getting the Stack Trace of an Exception
</a>
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e102. <a class="eglink" href="WorkQueue.html?l=rel">
Implementing a Work Queue
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See also:
<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Arrays">
Arrays
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Assertions">
Assertions
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Classes">
Classes
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Commands">
Commands
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Numbers">
Numbers
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Objects">
Objects
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#Strings">
Strings
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<a class="eglink" href="/egs/java.lang/pkg.html?l=rel#System%20Properties">
System Properties
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