MemorySessionDao should be propably abstract

Please consider different default configuration for caching of session.

Today i have spent a plenty of time trying to find the reason why i'm loosing my sessions.
(i'm using native mode)

Finally i have found that session were garbage-collected from that soft cache. which is default configuration for native mode.
So i have configured my security manager to use org.apache.shiro.cache.HashtableCacheManager which actually replaces the caching
by simple memory persistence.

I think this can be better default.

Anyway,please consider moving out from such thing as default wiring (made by/in constructors).

Personally speaking i think it is that is better to leave the decision on developer , what caching or other dependencies
will he use. I also know that requires higher understanding of your product, but at least forces lean persons ( like me) to do that.

The configuration can be made by spring, so all dependencies can be injected easily.

There can/should be made some reasonable scenarios for configuration depending on deployment like:
-single node

• clustered node .
• service
  -etc.

Sincerely,
Peter.