combine themeleaf error pages

Fix #1119

Author: mukeshk

src/main/java/ru/mystamps/web/feature/site/ErrorController.java

@@ -37,7 +37,7 @@ public class ErrorController {
 	private final SiteService siteService;
 
 	@RequestMapping(SiteUrl.NOT_FOUND_PAGE)
-	public void notFound(
+	public String notFound(
 			HttpServletRequest request,
 			@CurrentUser Integer currentUserId,
 			// CheckStyle: ignore LineLength for next 1 line
@@ -50,10 +50,12 @@ public void notFound(
 		String method = request.getMethod();
 
 		siteService.logAboutAbsentPage(page, method, currentUserId, ip, referer, agent);
+		
+		return SiteUrl.COMMON_ERROR_PAGE;
 	}
 
 	@RequestMapping(SiteUrl.INTERNAL_ERROR_PAGE)
-	public void internalError(
+	public String internalError(
 		// CheckStyle: ignore LineLength for next 3 lines
 		@RequestAttribute(name = RequestDispatcher.ERROR_EXCEPTION_TYPE, required = false) Class<?> exceptionType,
 		@RequestAttribute(name = RequestDispatcher.ERROR_EXCEPTION, required = false) Exception exception,
@@ -69,6 +71,7 @@ public void internalError(
 				exception
 			);
 		}
+		return SiteUrl.COMMON_ERROR_PAGE;
 	}
 
 	private static Object getNameOrAsIs(Class<?> clazz) {

src/main/java/ru/mystamps/web/feature/site/SiteUrl.java

@@ -39,9 +39,10 @@ public final class SiteUrl {
 	public static final String SITE_EVENTS_PAGE    = "/site/events";
 	public static final String CSP_REPORTS_HANDLER = "/site/csp/reports";
 
-	public static final String FORBIDDEN_PAGE      = "/error/403";
+	public static final String FORBIDDEN_PAGE      = "/error/status-code";
 	public static final String NOT_FOUND_PAGE      = "/error/404";
 	public static final String INTERNAL_ERROR_PAGE = "/error/500";
+	public static final String COMMON_ERROR_PAGE   = "/error/status-code";
 
 	static final String ROBOTS_TXT                 = "/robots.txt";
 	static final String SITEMAP_XML                = "/sitemap.xml";

src/main/resources/ru/mystamps/i18n/Messages.properties

@@ -96,15 +96,11 @@ t_password_again = Retype password
 t_activation_key = Activation key
 t_register = Register
 
-# error/403.html
+# error/status-code.html
 t_403_title = 403: forbidden
 t_403_description = Forbidden
-
-# error/404.html
 t_404_title = 404: page not found
 t_404_description = Requested page{0}not found
-
-# error/500.html
 t_500_title = 500: internal server error
 t_500_description = Internal{0}server error
 

src/main/resources/ru/mystamps/i18n/Messages_ru.properties

@@ -96,15 +96,11 @@ t_password_again = Пароль (ещё раз)
 t_activation_key = Код активации
 t_register = Зарегистрироваться
 
-# error/403.html
+# error/status-code.html
 t_403_title = 403: доступ запрещён
 t_403_description = Доступ запрещён
-
-# error/404.html
 t_404_title = 404: страница не найдена
 t_404_description = Запрашиваемая страница{0}не найдена
-
-# error/500.html
 t_500_title = 500: внутренняя ошибка сервера
 t_500_description = Внутренняя{0}ошибка сервера