this.messageCode = messageCode;
    }

    /**
     * Returns the message code for localized error messages.
     *
     * @return the message code
     */
    public VaMessenger<FessMessages> getMessageCode() {
        return messageCode;
    }

     * localized error messages appropriate for the user's language settings.
     *
     * @return The message code for error message localization
     */
    public VaMessenger<FessMessages> getMessageCode() {
        return messageCode;
    }

        // Verify different message codes
        assertEquals(unknownErrorCode, unknownException.getMessageCode());
        assertEquals(parseErrorCode, parseException.getMessageCode());
        assertNotSame(unknownException.getMessageCode(), parseException.getMessageCode());
    }

    @Test
    public void test_complexMessageCode() {

        // Verify
        assertEquals(loginErrorCode, loginException.getMessageCode());
        assertEquals(logoutErrorCode, logoutException.getMessageCode());
        assertNotSame(loginException.getMessageCode(), logoutException.getMessageCode());
    }

    @Test
    public void test_complexMessageCode() {

                if (logger.isDebugEnabled()) {
                    logger.debug("Metadata response.", e);
                }
                saveInfo(e.getMessageCode());
            } else {
                logger.warn("Failed to process metadata.", e);
                saveError(e.getMessageCode());
            }
            return redirect(LoginAction.class);
        }
    }

    /**

        } catch (final InvalidQueryException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Invalid query: {}", body.q, e);
            }
            throwValidationErrorApi(e.getMessageCode());
        } catch (final ResultOffsetExceededException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Invalid offset: {}", body.offset, e);
            }

        } catch (final InvalidQueryException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Invalid query: {}", form.q, e);
            }
            throwValidationError(e.getMessageCode(), this::asListHtml);
        } catch (final ResultOffsetExceededException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Invalid offset: {}", form.offset, e);
            }

            });
        } catch (final InvalidQueryException e) {
            if (logger.isDebugEnabled()) {
                logger.debug(e.getMessage(), e);
            }
            saveError(e.getMessageCode());
            return redirectToRoot();
        } catch (final ResultOffsetExceededException e) {
            if (logger.isDebugEnabled()) {
                logger.debug(e.getMessage(), e);
            }