synchronized (this)
synchronized (mutex)
        public boolean sendEvents(AjaxResponse response)        {            synchronized (this)            {                boolean alerts=false;                for (int i=0;i<_events.size();i++)                {                    Event event = (Event)_events.get(i);                    response.objectResponse("chat", event.toString());                    alerts |= event.isAlert();                }                _events.clear();                return alerts;            }        }