Caching use case data in session is generally not a good idea. Most web containers prefer HttpSession to be as small as possible. In clustered environments where session data is persisted to a common data store, the I/O cost can be expensive if the size of httpSession is large.

An alternative is to create a general purpose caching framework where use case data, as well as common read-only data, can be managed. The cache framework can use softly referenced objects, thereby working with the container''s garbage collector instead of application level garbage collection.