This is the WebScarab OpenSource project, hosted at
http://www.owasp.org/index.php/Category:OWASP_WebScarab_Project

It aims to become a tool that may be used automatically or interactively
to test web applications for their security.
WebScarab is written in 100% pure java and designed using a fairly clean
set of interfaces to allow for removal and substitution of existing
components, or addition of new analysis systems.

For more details, please see the URL above.