How to keep session alive?

["Szegedi, Attila" <sz...@scriptum.hu>]

I have a servlet that takes more time to process a request than the session
timeout. (A client sends many MBs of data in a POST request that the servlet
should somehow process). After the processing is done, the session has
expired. Can I stop this from happening somehow (the logic of my servlet
allows for periodically issuing some form of session keep-alive event,
however I simply do not know what that could be...)

Please respond to me directly as well as to list as I'm not subscribed to
tomcat-user.

TIA,
  Attila.