Java ThreadGroup .activeGroupCount ()

public int activeGroupCount()

//from   w ww.ja va  2  s.  c o m
public class Main {

  public static void main(String[] args) {
    ThreadGroupDemo tg = new ThreadGroupDemo();
  }
}

class ThreadGroupDemo implements Runnable {
  public ThreadGroupDemo() {
    ThreadGroup pGroup = new ThreadGroup("Parent ThreadGroup");

    ThreadGroup cGroup = new ThreadGroup(pGroup, "Child ThreadGroup");

    Thread t1 = new Thread(pGroup, this);
    System.out.println("Starting " + t1.getName());
    t1.start();

    Thread t2 = new Thread(cGroup, this);
    System.out.println("Starting " + t2.getName());
    t2.start();

    System.out.println("Active group(child) threads in \"" + pGroup.getName()
        + "\" = " + pGroup.activeCount());

  }

  public void run() {

    System.out.println(Thread.currentThread().getName()
        + " finished executing.");
  }
}