protected void handleException(Throwable t) {
    String msg = "Caught throwable while processing event " + eventType;
    LOG.error(msg, t);
    if (server != null && (t instanceof Error || t instanceof RuntimeException)) {
      server.abort(msg, t);
    }
  }
Event exception handler, may be overridden
@param t Throwable object
hbase-server/src/main/java/org/apache/hadoop/hbase/executor/EventHandler.java