diff -r f4608ad6c947 -r 2b270c714678 src/java/de/uapcore/lightpit/AbstractLightPITServlet.java
--- a/src/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Tue Dec 26 17:36:47 2017 +0100
+++ b/src/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Tue Dec 26 19:18:32 2017 +0100
@@ -87,7 +87,7 @@
     private ResponseType invokeMapping(Method method, HttpServletRequest req, HttpServletResponse resp)
             throws IOException, ServletException {
         try {
-            LOG.debug("invoke {}", method.getName());
+            LOG.trace("invoke {}#{}", method.getDeclaringClass().getName(), method.getName());
             return (ResponseType) method.invoke(this, req, resp);
         } catch (ReflectiveOperationException | ClassCastException ex) {
             LOG.error(String.format("invocation of method %s failed", method.getName()), ex);
@@ -242,6 +242,8 @@
             Locale sessionLocale = reqLocale.filter((rl) -> availableLanguages.map((al) -> al.contains(rl.getLanguage())).orElse(false)).orElse(Locale.ENGLISH);
             session.setAttribute(Constants.SESSION_ATTR_LANGUAGE, sessionLocale);
             LOG.debug("Settng language for new session {}: {}", session.getId(), sessionLocale.getDisplayLanguage());
+        } else {
+            LOG.trace("Continuing session {} with language {}", session.getId(), session.getAttribute(Constants.SESSION_ATTR_LANGUAGE));
         }
         
         req.setAttribute(Constants.REQ_ATTR_PATH, Functions.fullPath(req));