I just found some interesting behaviour when using request.getParameter("xxx");
On the first request everything was fine. Using the url http://localhost:8080/portal/index.html;jsessionid=004DF12089E81E6E17D6FD9384553DBA?ctrl:cmd=render&ctrl:window=esvportal.start.cmsWindow&xxx=121091 the request parameter xxx was 121091.
The strange behaviour happens if I klick on a link that generates another request. At this time I also get the request parameter xxx that is set to the same value as in the previous request although I do not set the parameter in the url: http://localhost:8080/portal/index.html?ctrl:cmd=render&ctrl:window=esvportal.channel_first_level.cmsWindow
After experiencing with the request I found out that the workaround for my problem is clearing the parameter map: request.getParameterMap().clear();
That works for my case but I'm interested whether this behaviour is correct? I would have expected that behaviour within the session.getAttribute("xxx"), but not in request.getParameter("xxx")