Which makes it invalid how? Think of a ruby dev team and the wish to extend the CI server?

These guys did: https://wiki.jenkins-ci.org/display/JENKINS/Jenkins+plugin+d... (plugins in JRuby)

I don't really get the problem though. Java is trivial to learn for anyone. It's not your main product, it's not going to take a massive amount of time for a single plugin. Just write it and be done...

It might be really easy to learn. But after having programmed Ruby for any significant time Java is very unpleasant to program ;)

Also just learning basics to do simple customizations is not enough. If something breaks you will not have a slightest idea how to debug and fix. With a Ruby CI server I can just stick a debugger and walk through the code.

> Think of a ruby dev team and the wish to extend the CI server?

It's not exactly a show stopper as long as they have the sourcecode.

If the team are capable enough to code Ruby and extend the CI server, then they either already know enough Java to do so or can learn it quickly enough to be effective.

Mainly yes.. shouts like " Java sxx" " I hate Java". The most relevant may be to resource usage: Jenkins would require more resources than the production machine in mid sized project. But in a world of commodity HW I'don't think this is a real issue