Java EE Cache Filter provides a collection of common Servlet filters for Java web applications allowing you to transparently set HTTP cache headers in order to enable browser caching.

Why does cache matter?

Web page designs are getting richer and richer, which means more scripts, stylesheets, images, and Flash in the page. A first-time visitor to your page may have to make several HTTP requests, but by using the Expires header you make those components cacheable. This avoids unnecessary HTTP requests on subsequent page views.
Browsers (and proxies) use a cache to reduce the number and size of HTTP requests, making web pages load faster.