try {
            userService.changePassword(username, form.newPassword);
            saveInfo(messages -> messages.addSuccessChangedPassword(GLOBAL));
        } catch (final Exception e) {
            logger.warn("Failed to change password for {}", username, e);
            throwValidationError(messages -> messages.addErrorsFailedToChangePassword(GLOBAL), toIndexPage);
        }
        return redirect(getClass());
    }

     * @param validationMessagesLambda lambda function that adds validation messages
     * @return concatenated string of localized validation messages separated by spaces
     */
    protected String getMessage(final VaMessenger<FessMessages> validationMessagesLambda) {
        final FessMessages messages = new FessMessages();
        validationMessagesLambda.message(messages);

        try {
            groupService.store(entity);
            saveInfo(messages -> messages.addSuccessCrudCreateCrudTable(GLOBAL));
        } catch (final Exception e) {
            logger.warn("Failed to process a request.", e);
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateCrudTable(GLOBAL, buildThrowableMessage(e)));
        }

                logger.warn("Failed to process a request.", e);
                throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateCrudTable(GLOBAL, buildThrowableMessage(e)));
            }
            return entity;
        }).orElseGet(() -> {
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateInstance(GLOBAL));
            return null;
        });

        body.dictId = dictId;
        validateApi(body, messages -> {});
        body.crudMode = CrudMode.CREATE;
        final SynonymItem entity = createSynonymItem(this, body, () -> {
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateInstance(GLOBAL));
            return null;
        }).orElseGet(() -> {
            throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToCreateInstance(GLOBAL));

                logger.warn("Failed to process a request.", e);
                throwValidationError(messages -> messages.addErrorsFailedToUploadStemmeroverrideFile(GLOBAL),
                        () -> redirectWith(getClass(), moreUrl("uploadpage/" + form.dictId)));
            }
            saveInfo(messages -> messages.addSuccessUploadStemmeroverrideFile(GLOBAL));

                logger.warn("Failed to create group: {}", form.name, e);
                throwValidationError(messages -> messages.addErrorsCrudFailedToCreateCrudTable(GLOBAL, buildThrowableMessage(e)),
                        this::asEditHtml);
            }
        }).orElse(() -> {
            throwValidationError(messages -> messages.addErrorsCrudFailedToCreateInstance(GLOBAL), this::asEditHtml);
        });
        return redirect(getClass());

            try {
                webConfigService.delete(entity);
                saveInfo(messages -> messages.addSuccessCrudDeleteCrudTable(GLOBAL));
            } catch (final Exception e) {
                logger.warn("Failed to process a request.", e);
                throwValidationErrorApi(messages -> messages.addErrorsCrudFailedToDeleteCrudTable(GLOBAL, buildThrowableMessage(e)));
            }
        }).orElse(() -> {

                throwValidationError(messages -> messages.addErrorsFailedToDeleteFile(GLOBAL, form.fileName), this::asListHtml);
            }
        }).orElse(() -> {
            throwValidationError(messages -> messages.addErrorsTargetFileDoesNotExist(GLOBAL, form.fileName), this::asListHtml);
        });
        saveInfo(messages -> messages.addSuccessDeleteFile(GLOBAL, form.fileName));

 * This validator provides validation functionality for Fess web actions with custom
 * message handling and runtime group validation.
 *
 * @param <MESSAGES> the type of user messages used by this validator
 */
public class FessActionValidator<MESSAGES extends UserMessages> extends ActionValidator<MESSAGES> {

    /**
     * Constructs a new FessActionValidator with the specified components.
     *