Interrupt a known thread in a known thread group

thread.java

    ThreadGroup[] threadGroups;
    int groupCount = 0;
    do {
      threadGroups = new ThreadGroup[threadGroup.activeGroupCount() * 2];
      groupCount = threadGroup.enumerate(threadGroups, false);
    } while (groupCount > threadGroups.length);

    for (int i = 0; i < threadGroups.length; i++) {
      ThreadGroup group = threadGroups[i];
      if (group != null && THREADGROUP_NAME.equals(group.getName())) {
        Thread[] threads;
        int threadCount = 0;
        do {
          threads = new Thread[group.activeCount() * 2];
          threadCount = group.enumerate(threads, false);
        } while (threadCount > threads.length);

        for (int j = 0; j < threads.length; j++) {
          Thread thread = threads[j];
          if (thread != null && THREAD_NAME.equals(thread.getName())) {
            thread.interrupt();
          }
        }
      }
    }

thank you java 1.0 apis.