jruby

https://github.com/jruby/jruby

Ruby

JRuby, an implementation of Ruby on the JVM

Gem.__ruby__

The path to the running Ruby interpreter.

Source | Google | Stack overflow

Edit

git clone [email protected]:jruby/jruby.git
cd jruby
open lib/ruby/stdlib/rubygems/defaults/jruby.rb

Contribute

# Make a new branch
git checkout -b -your-name--update-docs-Gem-__ruby__-for-pr

# Commit to git
git add lib/ruby/stdlib/rubygems/defaults/jruby.rbgit commit -m "better docs for Gem.__ruby__"

# Open pull request
gem install hub # on a mac you can `brew install hub`
hub fork
git push <your name> -your-name--update-docs-Gem-__ruby__-for-pr
hub pull-request

# Celebrate!