code: private void readPropertiesFile(final String rbFilename) {
  
          final File rbFile = new File(rbFilename);
  
          final String rbName = rbFile.getName().substring(0, rbFile.getName().lastIndexOf(".properties"));
  
          if (rbName == null || rbName.isEmpty()) {
              LOGGER.error(JRebirthMarkers.MESSAGE, "Resource Bundle must be not null and not empty");
          } else {
  
              LOGGER.info(JRebirthMarkers.MESSAGE, "Store ResourceBundle : {} ", rbName);
              try {
                  this.resourceBundles.add(ResourceBundle.getBundle(rbName));
              } catch (final MissingResourceException e) {
                  LOGGER.error(JRebirthMarkers.MESSAGE, "{} Resource Bundle not found", rbName);
              }
          }
      }
docs: Read a customized Message file to load all translated messages.
  
  @param rbFilename the resource bundle file to load