public class RunningThreads{

public static void main(String[] args) {

        ThreadGroup group = Thread.currentThread().getThreadGroup();
        ThreadGroup gp;
        while ((gp = group.getParent()) != null) {
            group = gp;
        }
        findThreads(group, "");
    }
   public static void findThreads(ThreadGroup group, String str) {
        System.out.println(str + "Group[" + group.getName() +   ":" + group.getClass()+"]");
        int count = group.activeCount();
        Thread[] threads = new Thread[count*2 + 10]; 
        count = group.enumerate(threads, false);
        for (int i=0; i<count; i++) {
            Thread t = threads[i];
            System.out.println(str + "  Thread[" + t.getName() + ":" + t.getClass() + "]");
        }
        int ct = group.activeGroupCount();
        ThreadGroup[] groups = new ThreadGroup[ct*2 + 10];
        ct = group.enumerate(groups, false);

        for (int i=0; i<ct; i++) {
            findThreads(groups[i], str + "  ");
        }
    }
}