private FileWatchdog createWatchDog() {
    FileWatchdog fileWatch = new FileWatchdog(file.getAbsolutePath()) {
      @Override
      protected void doOnChange() {
        if (started) {
          notifyListener();
        }
      }
    };
    fileWatch.setDelay(1000);
    fileWatch.setDaemon(true);
    fileWatch.setName("FileWatchdog:" + file.getName());
    return fileWatch;
  }
@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