I tried to follow this tutorial to deploy my jruby app on tomcat, but yet it always ends with:
--- Backtrace NoMethodError: undefined method `relative_ur
We had the same problem, and it was tracked down to the new version jruby-rack (1.1.1 IIRC). We downgraded to 1.0.10 and the problem went away. I'm not sure what the "root" of the problem was though.