OSCache is a widely used, high performance J2EE caching framework. In
addition to it's servlet-specific features, OSCache can be used as a
generic caching solution for any Java application. A few of its
generic features include:

* Caching of Arbitrary Objects - You are not restricted to caching
portions of JSP pages or HTTP requests. Any Java object can be cached.
* Comprehensive API - The OSCache API gives you full programmatic
control over all of OSCache's features.
* Persistent Caching - The cache can optionally be disk-based,
thereby allowing expensive-to-create data to remain cached even across
application restarts.
* Clustering - Support for clustering of cached data can be enabled
with a single configuration parameter. No code changes required.
* Expiry of Cache Entries - You have a huge amount of control over
how cached objects expire, including pluggable RefreshPolicies if the
default functionality does not meet your requirements.

http://java-source.net/open-source/cache-solutions