public String getCategoryValue(ResourceBundle messagesBundle) {
      if (keys.length == 1) {
        return messagesBundle.getString(keys[0]);
      }
      final StringBuilder buf = new StringBuilder();
      for (String key : keys) {
        buf.append(messagesBundle.getString(key));
      }
      return buf.toString();
    }
public String getCategoryValue(ResourceBundle messagesBundle)