code: public void run() {
      LOGGER.debug("begin scan for config file changes ...");
      try {
        Date lastModified = new Date(_xmlConfigFile.lastModified());
  
        if (_lastTimeRead == null || lastModified.after(_lastTimeRead)) {
          LOGGER.info("loading config file changes ...");
          this.loadServiceConfigFile();
          _lastTimeRead = new Date();
        }
      } catch (ConfigurationException e) {
        e.printStackTrace();
        LOGGER.error( "Error loading configuation file: ", e );
      }
      LOGGER.debug("finish scan for config file changes");
    }
docs: When the timer goes off, look for changes to the specified xml config file.
  For comparison, we are only interested in the last time we read the file. A
  null value for lastTimeRead means that we never read the file before.