I was interested in Java caching techniques a couple months ago (almost a year ago in fact) and looked into the various caching libraries available at that time. Srini Penchikala published an article @ OnJava.com this past December that looks in detail at caching with JCS, which is part of the Turbine Jakarta project. The article itself has some valuable insights, but more importantly it turns out that JSR 107 has a variety of implementations now, one of them on sourceforge called jcache, which just released an alpha version.