Ruby on Rails on GlassFish and with an Embedded Derby
By pelegri on Feb 21, 2007
Ashish is making Rails apps run well on GlassFish, and has been writing about it. His latest writeup describes how to take a RoR app, deploy it into GlassFish and have it use a Derby database embedded (the alternative is remote, where Derby runs in a separate process).
A few gotcha's, so check Ashish's blog for details if you are to do this.