Fix build on jruby.
Fix build on jruby.

shopittome/cruisecontrol.rb,onrooby/cruisecontrol.rb,shopittome/cruisecontrol.rb,shopittome/cruisecontrol.rb,shopittome/cruisecontrol.rb,onrooby/cruisecontrol.rb,thoughtworks/cruisecontrol.rb,onrooby/cruisecontrol.rb,onrooby/cruisecontrol.rb,thoughtworks/cruisecontrol.rb,shopittome/cruisecontrol.rb,thoughtworks/cruisecontrol.rb,shopittome/cruisecontrol.rb,onrooby/cruisecontrol.rb,thoughtworks/cruisecontrol.rb,thoughtworks/cruisecontrol.rb