Would like to hear from people about their experience with java clustering (ie. implementing HA solutions). aka . terracotta, JGroups etc. It doesn't have to be web apps. Experience writing custom stand alone servers would be great also.
UPDATE : I will be a bit more specific -> not that interested in Web App clustering (unless it can be pulled out and run standalone). I know it works. But we need a bit more than just session clustering. Examining solutions in terms of ease of programming, supported topologies (ie. single data center versus over the WAN ), number of supported nodes. Issues faced, workarounds. At the moment I am doing some POC (Proof of concept) work on Terracotta and JGroups to see if its worth the effort for our app (which is stand alone, outside of a web container).