private void notifyListener() {
    LOG.info("{} changed. Sending notification.", file);
    try {
      changeListener.accept(file);
    } catch (Exception e) {
      LOG.warn("Error while notifying " + this + " listener", e);
    }
  }
@param file to be watched
@param changeListener to be notified if the file content changes
ambari-server/src/main/java/org/apache/ambari/server/configuration/SingleFileWatch.java