code: public void initializeWithPropertiesFilename(String filename) throws ProbeHandlerConfigException {
  
      InputStream is;
      // try to load the properties file off the classpath first
  
      if (ConfigFileProbeHandlerPlugin.class.getResource(filename) != null) {
        is = ConfigFileProbeHandlerPlugin.class.getResourceAsStream(filename);
      } else {
        try {
          is = new FileInputStream(filename);
        } catch (FileNotFoundException e) {
          throw new ProbeHandlerConfigException("Error loading handler config for [" + this.getClass().getName() + "]", e);
        }
      }
  
      try {
        config.load(is);
      } catch (IOException e) {
        throw new ProbeHandlerConfigException("Error loading handler config for [" + this.getClass().getName() + "]", e);
      } finally {
        try {
          is.close();
        } catch (IOException e) {
          throw new ProbeHandlerConfigException("Error closing handler config for {" + this.getClass().getName() + "]", e);
        }
      }
  
      // Launch the timer task that will look for changes to the config file
      try {
        configFileScan = new Timer();
        configFileScan.scheduleAtFixedRate(new ConfigFileMonitorTask(this), 100, 10000);
      } catch (ConfigurationException e) {
        throw new ProbeHandlerConfigException("Error initializing monitor task.", e);
      }
  
    }
docs: Initialize the handler.