Error on Rack initialization with JRuby

Question

I am getting this error when starting JBoss with my application built with warbler:

Error: unable to initialize application 
org.jruby.rack.RackInitializationException: wrong number of arguments (1 for 0)

Callstack:

gems/gems/actionpack-3.0.9/lib/action_controller/railtie.rb:54:in `Railtie'
gems/gems/activesupport-3.0.9/lib/active_support/ordered_hash.rb:139:in `each'
org/jruby/RubyArray.java:1612:in `each'
gems/gems/activesupport-3.0.9/lib/active_support/ordered_hash.rb:139:in `each'
gems/gems/actionpack-3.0.9/lib/action_controller/railtie.rb:54:in `Railtie'
org/jruby/RubyKernel.java:2062:in `instance_eval'
gems/gems/activesupport-3.0.9/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
gems/gems/activesupport-3.0.9/lib/active_support/lazy_load_hooks.rb:43:in `run_load_hooks'
org/jruby/RubyArray.java:1612:in `each'
gems/gems/activesupport-3.0.9/lib/active_support/lazy_load_hooks.rb:42:in `run_load_hooks'
gems/gems/actionpack-3.0.9/lib/action_controller/base.rb:232:in `Base'
gems/gems/actionpack-3.0.9/lib/action_controller/base.rb:169:in `ActionController'
gems/gems/actionpack-3.0.9/lib/action_controller/base.rb:3:in `(root)'
gems/gems/actionpack-3.0.9/lib/action_controller/base.rb:48:in `Railtie'
org/jruby/RubyKernel.java:2079:in `instance_exec'
gems/gems/railties-3.0.9/lib/rails/initializable.rb:25:in `run'
gems/gems/railties-3.0.9/lib/rails/initializable.rb:50:in `run_initializers'
org/jruby/RubyArray.java:1612:in `each'
gems/gems/railties-3.0.9/lib/rails/initializable.rb:49:in `run_initializers'
gems/gems/railties-3.0.9/lib/rails/application.rb:134:in `initialize!'
org/jruby/RubyKernel.java:2093:in `send'
gems/gems/railties-3.0.9/lib/rails/application.rb:77:in `method_missing'
config/environment.rb:5:in `(root)'
org/jruby/RubyKernel.java:1038:in `require'
config/environment.rb:167:in `load_environment'
classpath:/./jruby/rack/rails.rb:172:in `to_app'
classpath:/./jruby/rack/rails.rb:192:in `new'
 <web.xml>:1:in `(root)'
org/jruby/RubyKernel.java:2062:in `instance_eval'
classpath:/./vendor/rack-1.3.5/rack/builder.rb:51:in `initialize'
<web.xml>:1:in `(root)'

Any ideas?

Answer 1

We had the same problems with Rails 3.0.11 / JBoss 5 and the latest jruby-rack. To sort this out we had to use jruby-rack 1.0.10

Please try to put this line into your Gemfile:

gem 'jruby-rack', '1.0.10'

Answer 2

I got this same error when upgrading an app to Rails 3. The problem was related to invoking ActionController::Base.relative_url_root=, which is supposed to emit a deprecation warning, but it was busted in Rails 3.0.10.

My solution was to upgrade to jruby-rack 1.1.4 and rack 1.2.5.