It's very hard to do this using one Tomcat instance. It's very easy to do this using two Tomcat instances (call them Tomcat1 and Tomcat2) and a load balancer (Apache httpd should be fine for this job).
In normal use, Tomcat1 is running. The load balancer directs all users to Tomcat1. Tomcat2 could even be stopped. To upgrade, you upgrade Tomcat2 (and start it if needed) and tell the load balancer that new sessions should be sent to Tomcat2. Once all user sessions are off Tomcat1, you upgrade it and tell the load balancer to direct new sessions to Tomcat1. Once all user sessions are off Tomcat2, you can shut it down again or leave it running for fault tolerance. If you have enough RAM on your server (and the load is low enough), you could even run all three of Tomcat1, Tomcat2 and httpd on the same server. Does this help? - Peter On 30 April 2010 14:46, Gabriele Bulfon <gbul...@sonicle.com> wrote: > Hello, > I don't know if I'm asking something stupid, but I'm investigating this for > days, and found > nothing around. > > Updating a java webapp can be a problem when this java webapp is being ised > 24/7 by users, > and many of them have sessions running for all the working hours. > Consider that this webapp consists of many instance classes being created > during session startup. > How can I manage updates of the webapp classes without having to reload the > webapp? > What I would like is that users inside the application to continue to see > the old version, > while new ones logging in would see the latest one. > > I don't know if there is any way for this.... > Thanks > Gabriele. > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org >
