What is cache invalidation? How it works?

[juzepeleteiro]

What is cache invalidation? How it works?

[ryanho]

Cache Invalidation are most useful in a clustered context where Entity Beans are operating under Commit Option A. It ensures that we can benefit from the caching performance gains of Commit Option A while ensuring that the Cache stays current.

This article explains it pretty thoroughly

http://www.onjava.com/pub/a/onjava/2003/05/28/jboss_optimization.html