jruby 1.7.8 (1.9.3p392) 2013-11-14 0ce429e on Java HotSpot(TM) Client VM 1.7.0_45-b18 [Windows XP-x86]

According to comments from @headius in issue #1236, directory
lib/ruby/gems/shared/gems
should contain "stub gems" for Rake and RDoc.

• RDoc gem is completely missing.
• Rake gem seems to be a complete gem, not just a "stub gem".