JRuby now available on Heroku

Change effective on 11 June 2015

The Ruby stack now supports JRuby

To use JRuby, add this to your Gemfile:

ruby '2.2.2', :engine => 'jruby', :engine_version => ''

The JRuby release notes can be found on the JRuby website.

Note: This version of JRuby is not suitable for production applications. However, it can be used to test that your application is ready for JRuby