code: public static FacesMessage getMessage(String bundleBaseName, Locale locale, String messageId, Object params[])
      {
        if (bundleBaseName == null)
        {
            throw new NullPointerException(
                "Unable to locate ResourceBundle: bundle is null");
        }
  
        ResourceBundle bundle = ResourceBundle.getBundle(bundleBaseName, locale);
  
        return getMessage(bundle, messageId, params);
      }
docs: Retrieve the message from a specific bundle. It does not look on application message bundle
  or default message bundle. If it is required to look on those bundles use getMessageFromBundle instead
  
  @param bundleBaseName baseName of ResourceBundle to load localized messages
  @param locale current locale
  @param messageId id of message
  @param params parameters to set at localized message
  @return generated FacesMessage