public void notifyThreadBusy(final Thread thread){
  if (thread == null) {
    return;
  }
synchronized (activationLock) {
synchronized (mainLock) {
      if (blockerThread == null) {
        activateBlockerThread();
      }
 else       if (isReadyToShutdown()) {
        mainLock.notifyAll();
        timeoutPassed=false;
      }
      busyThreadSet.add(thread);
    }
  }
}

public void notifyThreadBusy ( final Thread thread ) { if ( thread == null ) { return ; } synchronized ( activationLock ) { synchronized ( mainLock ) { if ( blockerThread == null ) { activateBlockerThread ( ) ; } else if ( isReadyToShutdown ( ) ) { mainLock . notifyAll ( ) ; timeoutPassed = false ; } busyThreadSet . add ( thread ) ; } } }
add a specified thread to the set of busy event dispatch threads . if this set already contains the specified thread or the thread is null , the call leaves this set unchanged and returns silently .
