code: public static ResourceBundle getResourceBundle(File location, String name, Locale locale) {
          File[] files = new File[] { new File(location, name + "_" + locale.toString() + RESOURCE_FILE_EXT),
                                     new File(location, name + "_" + locale.getLanguage() + RESOURCE_FILE_EXT),
                                     new File(location, name + RESOURCE_FILE_EXT) };
          for (File file : files) {
              if (exists(file)) {
                  try {
                      return new PropertyResourceBundle(new FileReader(file));
                  } catch (IOException e) {
                      if (logger.isLoggable(Level.FINE)) {
                          logger.fine("The resource file was not loaded. The exception is " + e.getMessage());
                      }
                  }
              }
          }
          return null;
      }
docs: find the best matching resouce bundle of the specified resouce file name.