The next release of Buildr <http://incubator.apache.org/buildr/> is going multi-lingual. We already have support for Java and Scala, but it's hackish and a pig to extend. Starting with 1.3, it will be easy to drop in support for new languages, say building Java and Scala code side by side, or mixing in Flash for the client side.
The design I went with is granular enough that you can mix projects in different languages, but also compile in one language and run test cases in another. Originally I was thinking of using RSpec to unit test Java code. Thanks to Ola Bini<http://ola-bini.blogspot.com/2007/12/jtestr-01-released.html>, we now have JTestR <http://jtestr.codehaus.org/Getting+Started>. And being an Ant task, it only takes a few lines of Ruby code (and zero lines of XML) to make it work. Anyone wants to give it a try? Assaf
