Http session management, store only strings and primitives.
Possibilities to cover
strangler approach (strangling different parts of architecture, how to do that)
Project organization patterns
User stories using the domain language.
Application integration
Scheduler architecture: out-of-process?, clustering
water mark
defining locks in database
avoiding starvation and duplication of jobs
handling race condition using offline locks
Include some hibernate related patterns
Setting up fine grained caching