Zero downtime deployment for Java apps

Question

I am trying to build the very lightweight solution for zero downtime deployment for Java apps. For the sake of simplicity lets think that we have two servers. My solution is to

Answer 1

Rolling upgrade is indeed a good solution, provided your load-balancer supports this option (server starvation). Another solution is to use OSGi-enabled application servers, to hot-replace parts or whole of your application.

I would recommend the first one. SpringSource's AMS supervision console can take down a cluster of tcServer (a custom tomcat on steroids), and IIRC do the rolling upgrade automatically (but check the docs).