Your answer is right, but maybe the question is not. The man should have asked: How does Weblogic implements
Weblogic has several ways to implement session persistence (to be more accurate: session [B]replication[B]) depending on your architecture:
If you have a single server, session is persisted "in memory", but if you have a cluster, session must be replicated to all servers.
Weblogic offer basically 2 ways for session replication: using the network (by sending multicast messages to groups of servers) or using a database to persist the serialized session objects.
Which one is better? That depend on several factors (the number of servers in the cluster, the load balancing method you use, etc.)
If you are interested on details or other aproaches, check Bea's doc
[ June 07, 2005: Message edited by: Pedro Gongora ]