code: public void clearIdleThreads()
    {
      _launcher.resetThrottle();
      
      int idleCount = _idleThreadRing.size();
      
      ThreadAmp thread;
  
      while (idleCount-- > 0 && (thread = _idleThreadRing.poll()) != null) {
        thread.close();
      }
    }
docs: interrupts all the idle threads.