code: public void fire() {
  		ArrayList<Runnable> listeners;
  		synchronized (this) {
  			if (this.listeners == null) return;
  			listeners = new ArrayList<>(this.listeners);
  		}
  		for (int i = 0; i < listeners.size(); ++i)
  			listeners.get(i).run();
  	}
docs: Fire this event, or in other words call the listeners.