diff -r c5d6820d884e -r 1e6f16fad3a5 src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java
--- a/src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Sat Oct 31 10:54:20 2020 +0100
+++ b/src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Thu Nov 05 13:37:48 2020 +0100
@@ -108,7 +108,7 @@
         throw new UnsupportedOperationException("Non-exhaustive if-else - this is a bug.");
     }
 
-    private ResponseType invokeMapping(Map.Entry<PathPattern, Method> mapping, HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws IOException {
+    private void invokeMapping(Map.Entry<PathPattern, Method> mapping, HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws IOException {
         final var pathPattern = mapping.getKey();
         final var method = mapping.getValue();
         try {
@@ -128,19 +128,17 @@
                     paramValues[i] = pathPattern.obtainPathParameters(sanitizeRequestPath(req));
                 }
             }
-            return (ResponseType) method.invoke(this, paramValues);
+            method.invoke(this, paramValues);
         } catch (InvocationTargetException ex) {
             LOG.error("invocation of method {}::{} failed: {}",
                     method.getDeclaringClass().getName(), method.getName(), ex.getTargetException().getMessage());
             LOG.debug("Details: ", ex.getTargetException());
             resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex.getTargetException().getMessage());
-            return ResponseType.NONE;
         } catch (ReflectiveOperationException | ClassCastException ex) {
             LOG.error("invocation of method {}::{} failed: {}",
                     method.getDeclaringClass().getName(), method.getName(), ex.getMessage());
             LOG.debug("Details: ", ex);
             resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex.getMessage());
-            return ResponseType.NONE;
         }
     }
 
@@ -176,12 +174,6 @@
                         );
                         continue;
                     }
-                    if (!ResponseType.class.isAssignableFrom(method.getReturnType())) {
-                        LOG.warn("{} is annotated with {} but has the wrong return type - 'ResponseType' required",
-                                method.getName(), RequestMapping.class.getSimpleName()
-                        );
-                        continue;
-                    }
 
                     boolean paramsInjectible = true;
                     for (var param : method.getParameterTypes()) {
@@ -388,18 +380,8 @@
         );
     }
 
-    private void forwardAsSpecified(ResponseType type, HttpServletRequest req, HttpServletResponse resp)
-            throws ServletException, IOException {
-        switch (type) {
-            case NONE:
-                return;
-            case HTML:
-                req.getRequestDispatcher(SITE_JSP).forward(req, resp);
-                return;
-            // TODO: implement remaining response types
-            default:
-                throw new AssertionError("ResponseType switch is not exhaustive - this is a bug!");
-        }
+    protected void renderSite(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        req.getRequestDispatcher(SITE_JSP).forward(req, resp);
     }
 
     private void doProcess(HttpMethod method, HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
@@ -428,7 +410,7 @@
         if (fullPath.startsWith("/error/")) {
             final var mapping = findMapping(method, req);
             if (mapping.isPresent()) {
-                forwardAsSpecified(invokeMapping(mapping.get(), req, resp, null), req, resp);
+                invokeMapping(mapping.get(), req, resp, null);
             }
             return;
         }
@@ -447,7 +429,7 @@
                 // call the handler, if available, or send an HTTP 404 error
                 final var mapping = findMapping(method, req);
                 if (mapping.isPresent()) {
-                    forwardAsSpecified(invokeMapping(mapping.get(), req, resp, dao), req, resp);
+                    invokeMapping(mapping.get(), req, resp, dao);
                 } else {
                     resp.sendError(HttpServletResponse.SC_NOT_FOUND);
                 }