I'm trying to set the httponly flag on the JSESSIONID cookie. I'm working in Java EE 5, however, and can't use setHttpOnly(). First I tried to create my own JSESSIONID cookie from within the servlet's doPost() by using response.setHeader(). When that didn't work, I tried response.addHeader(). That didn't work either. Then, I learned that the servlet handled converting the session into a JSESSIONID cookie and inserting it into the http header so if I want to play with that cookie, I'll have to write a filter. I wrote a filter and played with setHeader()/addHeader() there, again to no avail. Then, I learned that there's some flush/close action going on in the response object before it gets to the filter so if I want to manipulate the data, I need to extend HttpServletResponseWrapper and pass that to filterChain.doFilter(). This is done but I'm still not getting results. Clearly I'm doing something wrong but I don't know what.

I'm not sure if this is at all relevant to the question at hand but no html document is being returned by the servlet to the browser. All that's really happening is that some objects are being populated and returned to a JSP document. I've sort of assumed that The Session object is turned into a JSESSIONID cookie and wrapped -- along with the objects added to the request -- in an http header before being sent to the browser.

I'd be happy to post some code but I want to rule out the possibility that my difficulties stem from a misunderstanding of the theory first.