diff -r 005d27918b57 -r f4608ad6c947 src/java/de/uapcore/lightpit/AbstractLightPITServlet.java
--- a/src/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Sat Dec 23 17:28:19 2017 +0100
+++ b/src/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Tue Dec 26 17:36:47 2017 +0100
@@ -31,13 +31,17 @@
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.util.Arrays;
 import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -49,6 +53,8 @@
     
     private static final Logger LOG = LoggerFactory.getLogger(AbstractLightPITServlet.class);
     
+    private static final String HTML_FULL_DISPATCHER = Functions.jspPath("html_full");
+    
     /**
      * Store a reference to the annotation for quicker access.
      */
@@ -164,29 +170,43 @@
         LOG.trace("{} destroyed", getServletName());
     }
     
+    /**
+     * Sets the name of the dynamic fragment.
+     * 
+     * It is sufficient to specify the name without any extension. The extension
+     * is added automatically if not specified.
+     * 
+     * The fragment must be located in the dynamic fragments folder.
+     * 
+     * @param req the servlet request object
+     * @param fragmentName the name of the fragment
+     * @see Constants#DYN_FRAGMENT_PATH_PREFIX
+     */
+    public void setDynamicFragment(HttpServletRequest req, String fragmentName) {
+        req.setAttribute(Constants.REQ_ATTR_FRAGMENT, Functions.dynFragmentPath(fragmentName));
+    }
     
     /**
-     * Sets several requests attributes, that can be used by the JSP.
+     * Specifies the name of an additional stylesheet used by the module.
+     * 
+     * Setting an additional stylesheet is optional, but quite common for HTML
+     * output.
+     * 
+     * It is sufficient to specify the name without any extension. The extension
+     * is added automatically if not specified.
      * 
      * @param req the servlet request object
-     * @see Constants#REQ_ATTR_PATH
-     * @see Constants#REQ_ATTR_MODULE_CLASSNAME
-     * @see Constants#REQ_ATTR_MODULE_INFO
+     * @param stylesheet the name of the stylesheet
      */
-    private void setGenericRequestAttributes(HttpServletRequest req) {
-        req.setAttribute(Constants.REQ_ATTR_PATH, Functions.fullPath(req));
-
-        req.setAttribute(Constants.REQ_ATTR_MODULE_CLASSNAME, this.getClass().getName());
-
-        moduleInfoELProxy.ifPresent((proxy) -> req.setAttribute(Constants.REQ_ATTR_MODULE_INFO, proxy));
+    public void setStylesheet(HttpServletRequest req, String stylesheet) {
+        req.setAttribute(Constants.REQ_ATTR_STYLESHEET, Functions.enforceExt(stylesheet, ".css"));
     }
     
     private void forwardToFullView(HttpServletRequest req, HttpServletResponse resp)
             throws IOException, ServletException {
         
-        setGenericRequestAttributes(req);
         req.setAttribute(Constants.REQ_ATTR_MENU, getModuleManager().getMainMenu());
-        req.getRequestDispatcher(Functions.jspPath("full.jsp")).forward(req, resp);
+        req.getRequestDispatcher(HTML_FULL_DISPATCHER).forward(req, resp);
     }
     
     private Optional<HandlerMethod> findMapping(HttpMethod method, HttpServletRequest req) {
@@ -212,6 +232,22 @@
     
     private void doProcess(HttpMethod method, HttpServletRequest req, HttpServletResponse resp)
             throws ServletException, IOException {
+        
+        HttpSession session = req.getSession();
+        
+        // choose the requested language as session language (if available) or fall back to english, otherwise
+        if (session.getAttribute(Constants.SESSION_ATTR_LANGUAGE) == null) {
+            Optional<List<String>> availableLanguages = Functions.availableLanguages(getServletContext()).map(Arrays::asList);
+            Optional<Locale> reqLocale = Optional.of(req.getLocale());
+            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());
+        }
+        
+        req.setAttribute(Constants.REQ_ATTR_PATH, Functions.fullPath(req));
+        req.setAttribute(Constants.REQ_ATTR_MODULE_CLASSNAME, this.getClass().getName());
+        moduleInfoELProxy.ifPresent((proxy) -> req.setAttribute(Constants.REQ_ATTR_MODULE_INFO, proxy));
+        
         Optional<HandlerMethod> mapping = findMapping(method, req);
         if (mapping.isPresent()) {
             forwardAsSepcified(mapping.get().apply(req, resp), req, resp);