I remember this blog post about how optimizing method calls becomes much harder with refinements (from MRI Ruby 2.1): http://blog.headius.com/2012/11/refining-

I remember this blog post about how optimizing method calls becomes much harder with refinements (from MRI Ruby 2.1): http://blog.headius.com/2012/11/refining-ruby.html http://blog.headius.com/2012/11/refining-ruby.html It looks like JRuby has refinements now but maybe not great support for them (based on just some quick Googling): https://github.com/jruby/jruby/issues/1062 https://github.com/jruby/jruby/issues/1062 So I'm curious if anything tested in the article has refinements support. Personally I'm still skeptical of refinements, but I guess JRuby will have to support them or more and more gems will start to break.