Question

I’ve always taken for granted the JSESSIONID cookie created for every fresh request for a given client when developing applications using the servlet specification. But after giving it a bit of thought, isn’t is more logical for the servlet container to create a cookie header only after the session has been requested and created in code? For clients who have their cookies disabled, won’t it end up creating a new HttpSession for each request made?

Please let me know if the question is still unclear so I can edit it. TIA.

Answer 1

A new Session will not be created by the Servlet container by default unless the Servlet actually creates it explicitly. Just because in the Header a JSEESIONID is being populated does not mean that there has to be a seesion on the server. An exception to this is in JSPs that by default create a Session if one is not there unless <%@ page session=”false” %>

As far as not having cookies turned on:

A web container can use several
methods to associate a session with a
user, all of which involve passing an
identifier between the client and the
server. The identifier can be
maintained on the client as a cookie,
or the web component can include the
identifier in every URL that is
returned to the client.

If your application uses session
objects, you must ensure that session
tracking is enabled by having the
application rewrite URLs whenever the
client turns off cookies. You do this
by calling the response’s
encodeURL(URL) method on all URLs
returned by a servlet. This method
includes the session ID in the URL
only if cookies are disabled;
otherwise, it returns the URL
unchanged.