I've got a requirement for a server process to subscribe to some topic
JMS messages, hold them in a cache, and write them to a database. I'm
considering writing an MDB to gather the JMS messages and write them
to the database while using a static singleton helper class to cache
the JMS messages. Can I count on WLS to keep the singleton object in
memory? Is there a better way to do this?

Using WLS 7.01.