ThreadGroup .activeCount()

[Anthony Smith]

I have a simple jsp page that has the following info on it:
(removed the html and jsp tags)




Runtime rt = Runtime.getRuntime();
// forcibly suggest garbage collection
System.gc();

// get the primordial threadgroup
ThreadGroup tg = Thread.currentThread().getThreadGroup();
while (tg.getParent()!=null) { tg=tg.getParent(); }

jtps.getAvailableThreadCount()
jtps.getQueueLength()
jtps.getThreadCount()
rt.totalMemory()
rt.freeMemory()
tg.activeCount()

Why does the value of tg.activeCount() get larger every time this page is called? Better yet, why does the value of tg.activeCount() never get smaller?

[Marlene Miller]

Hi Anthony, I don�t know the answer to your question, but I have a suggestion. ThreadGroup.enumerate will give you a list of the active threads.

class Test {
   public static void main(String[] args) {
      ThreadGroup tg = Thread.currentThread().getThreadGroup();
      while (tg.getParent()!=null) { tg=tg.getParent(); }
//
      int count = tg.activeCount();
      Thread[] t = new Thread[count];
      System.out.println(count); // just curious
//
      int count2 = tg.enumerate(t);
      System.out.println(count2); // just curious
//
      for (int i = 0; i < count2; i++)
         System.out.println(t[i]); // print name, priority, group
   }
}
//
5
5
Thread[Reference Handler,10,system]
Thread[Finalizer,8,system]
Thread[Signal Dispatcher,10,system]
Thread[CompilerThread0,10,system]
Thread[main,5,main]