[mattknox]

Twitter never used Jruby in any significant capacity. Note that the article she cited ( http://www.infoq.com/articles/twitter-java-use ) said we were evaluating jruby, but chose not to use it because the tooling around MRI was much better (in substantial part due to the efforts of twitter's backend team at the time).

We probably could have made a great jruby memcached/MySQL/thrift client, but it wasn't clear that doing so would have much performance win, as jruby itself wasn't dramatically faster than MRI. It would have, however, made it really easy for us to offload intense bits of code to java code, which probably would have been a faster upgrade path than rewriting in scala as we did.

[fizx]

Our production thrift code generator (now at https://github.com/twitter/scrooge) was JRuby for about a year, before Robey decided it was an abomination and rewrote it in scala.

JRuby was easy because you can Maven require it from a Java project. Ruby already has a Thrift IDL parser, so I just stole the AST from that, and used an ERb template to write out corresponding scala. The whole thing was maybe 200LOC.

But yeah, that's the only JRuby that ever did anything production related at Twitter.

[spimmy]

ahh, thanks for the clarification. :) (edited the post to be more accurate)