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GitHub User: kares
Ryan did not mention this explicitly, but it might not be obvious to some: You do not have to "deal" with Capistrano + JRuby 1.7 issues (Highline, SSH Forwarding). It's perfectly fine to use MRI while invoking the cap commands on your machine, you "only" need JRuby on the remote server where Trinidad lives.
One might also consider using the current "stable" version of JRuby on production 1.6.7 if you run into any specific issues with 1.7 (it's still a preview version although pretty stable).
no, Unicorn (similar to Mongrel) uses some native code thus it won't compile on JRuby.