How can I write EJBs that will run (unmodified) in any EJB-Container? What do I have to pay attention to?
When writing EJBs, do not use any vendor specific packages. Stick to javax packages (as per EJB spects). If you observe this rule, your EJB s should run on any App server.
Also, check EJB 2.0 spects. They define minimum interoperability standards between app servers using RMI - IIOP. But I did not find whether it's mandatory for the vendors or not. I am waiting for the final EJB 2.0 spec to be released.