Mozilla Labs last week released a new version of Prism, a single-site browser system that brings web applications to the desktop. The latest version is designed to work as a Firefox extension rather than as a separate XUL application.

http://labs.mozilla.com/2008/03/major-update-to-prism-first-prototype-of-browser-integration/

http://wiki.mozilla.org/Prism/Scripting

Roughly, you can run server side code offline. The interesting part is the lightweight browser. It does not support java (I think), but who knows?

Edit: after more careful reading on my part, it is more like a packager, no server side code locally, but the offline-lightweight stands.

Βαγγέλης Μαρινάκης