JRuby 9.0.0.0.pre2 now available on Heroku

Change effective on 28 April 2015

The Ruby stack now supports JRuby 9.0.0.0.pre2.

To use JRuby 9.0.0.0.pre2, add this to your Gemfile:

ruby '2.2.2', :engine => 'jruby', :engine_version => '9.0.0.0.pre2'

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 9.0.0.0.