OSCache is a widely used, high performance J2EE caching framework
OSCache solves fundamental problems for dynamic websites:
Caching Dynamic Content - Dynamic content of some form must often be executed during each request, but sometimes that content does not change every request. Caching the whole page does not help because sections of the page change every request.
OSCache solves this problem by providing a means to cache sections of JSP pages.
Caching Binary Content - Generated images and PDFs can be very costly in terms of server load.
OSCache solves this problem through a Servlet 2.3 CachingFilter which can cache any URI (such as an entire page or a generated image/PDF)
Error Tolerance - If one error occurs somewhere on your dynamic page, chances are the whole page will be returned as an error, even if 95% of the page executed correctly.
OSCache solves this problem by allowing you to serve the cached content in the event of an error, and then reporting the error appropriately.