Assuming you have a productive java application and don't want to have (even small) downtimes for software updates (including updated .class files) to take effect.
What infrastructure / server / tools do you use to achieve this?
Any experiences are much appreciated! Could be anything like two servers where one is updated while the other does the "old" job, features of e.g. a Tomcat server or tools enabling this.
It's not entirely clear from your description, but I'm guessing you're talking about Java EE and not Java SE applications? Java SE, we just use JNLP for deployment. Java EE, where we use Glassfish as the container and it has an option to install a new version without interrupting current sessions. We're not super heavy users, so I'm not absolutely positive that it has prevented an issue, but we've never had an issue. Our Tomcat EE users just get rudely bumped periodically when we do updates and are used to it at this point. :-(
