With all the blog posts about JRuby being posted, I thought I would
finally try JRuby myself.
I tested it on my genetic algorithms library. Lots of metaprogramming
going on in the initialization, and a lot of calculations afterwards
using the generated modules and classes.

First tried my tests.
Finished in 34.726 seconds.
33 tests, 626 assertions, 0 failures, 0 errors
That's better than 1.9, which couldn't handle some of the metaprogramming.

Then tried a benchmark:
1.8  : 676.75 seconds  (ubuntu/apt-get)
1.9  : 161.99 seconds  (svn/-O3/no enable-pthread)
JRuby: 302.23 seconds  (java opts -server, jruby +C)

Did JRuby just outperform 1.8 by a factor >2 ?
I'm impressed. Great job JRuby team.