Following on from his original interview with Charles Nutter and Thomas Enebo of the JRuby team, Pat Eyler has interviewed the team again (read part 1 then part 2), with the addition of Ola Bini. Both parts are quite long and go into a lot of detail about JRuby and Ruby's existence under the Java umbrella.

In Part 1, Ola comments:

I'm tackling performance from my side, by creating extensions in Java instead of Ruby (YAML and ZLib, for example).

JRuby might feel like an alternate bizarro reality, but these guys are doing a great job while staring one giant mountain in the face. Intriguingly, it may be that the official Ruby implementation developers could benefit from improvements made in JRuby, as Thomas Enebo explains:

I suspect that the C team could use some stuff we are doing. I am not sure I would spend that time right now. Once we are closer to 1.0 status I think our internals will be quite a bit simpler and this may be a good time to look at how we are doing things. At a minimum, it may generate a fresh set of ideas for them. The sharing of ideas is always good for creating a better piece of software.

Very in-depth and an engrossing read if the finer details of implementing parsers, interpreters or software engineering are your bag. Thanks to Pat Eyler for some great interviews.