Spring: long-term store non-serializable objects in cache

Spring: long-term store non-serializable objects in cache

I need somehow to save non-serializable session. There is no hope to
serialize it, and serialize session is bad architect approach. So, I start
thinking about saving List in my Spring cache. It is for architecture
reasons, not performance.
Questions:
Can I save non-serializable session object in spring cache?
Is it good idea for long-term storage?
Have spring on demand caching? I mean instead of using method-annotations
use something like cache.save(session) and cache.remove(session)?