Java EE (Java Enterprise Edition) General Discussion

hi experts,

If I have several websites running on the same server. Most of the are sub-domains of the same domain, they share the same database, but each sub-domain will have their own web-apps(This also means that they are running on a different java virtual machine, right? ). My question is that how can I make them communicate with each other. Also, will there be any conflict with the database insert/update issues, and How do I solve that?


For example, if one user is already logon from "tips.mydomain.com", then when the users goes to another sub-domain, say "java.mydomain.com", he/she doesn't need to re-login again.


thanks.