trying to build jruby-rack

gistfile1.txt

$ # in my project's rails root
$ git clone https://github.com/jruby/jruby-rack.git
$ cd jruby-rack
$ rake gem

mkdir -p target/classes
mvn org.jruby.plugins:jruby-rake-plugin:classpath -Djruby.classpath.scope=test
rake aborted!
Command failed with status (127): [mvn org.jruby.plugins:jruby-rake-plugin:cl...]

Tasks: TOP => spec => compile => target/classpath.rb
(See full trace by running task with --trace)