code: private static String getLocalizedOrCode(String bundleName,
                                               Locale locale,
                                               String code,
                                               String[] values) {
          ResourceBundle bundle = null;
          if (bundleName != null) {
              bundle = ResourceBundle.getBundle(bundleName, locale);
          }
          if (bundle == null) {
              return code;
          }
          String locMessage = bundle.getString(code);
          if (locMessage == null) {
              return code;
          }
          if (values == null) {
              return locMessage;
          }
          return MessageFormat.format(locMessage, (Object[]) values);
      }
docs: Gets the message from the resource bundle, formatting it if needed, and
  on failure, just returns the code.
  
  @param bundleName
  The ResourceBundle where the message is defined.
  @param locale
  The preferred locale.
  @param code
  The message key.
  @param values
  The replacement values, assumed empty if null.
  @return The detail messages, with {num}-indexed placeholders populated,
  if needed.