I am giving a Streamlined talk tonight at the NovaRUG, and I am giving a JRuby talk next week at the Atlanta No Fluff, Just Stuff symposium. I sense a chocolate-and-peanut-butter opportunity here...

(2 hours pass)

Success. Following Charles's instructions here, I got JRuby, Rails, and a Rails scaffold up and running without major incident. Streamlined, however, balked at the code generation phase. I posted a question on the jruby-user list, and within minutes had the answer from Charles: the following syntax is not OK in JRuby, and apparently will be removed from Ruby 2.0 as well:

  opt.on("--authentication=auth_lib",
  "Use authentication, and choose library (AAA)") {|options[:auth_lib]| }

A quick regexp replace to this form did the trick:

  opt.on("--authentication=auth_lib",
  "Use authentication, and choose library (AAA)") { |val| options[:auth_lib] = val }

[Note: Typo mentioned in the comments has been fixed. Thanks Jim.]

Streamlined (trunk or 0.0.6) now runs on JRuby on Rails. Bring on those funky enterprise databases!