I am guessing -S spec/views/... is the real problem with this, so I am making it a subtask of the parent issue.

I have the same problem using JRuby 1.1.6 and Rails 2.2.2 with the rspec_on_rails plugin, where all the specs run under the normal jruby -S rake spec

/home/zinger/devel/src/java/jruby/jruby-1.1.6/bin/jruby -S script/spec -O spec/spec.opts spec/controllers/deploys_controller_spec.rb. . (test list omitted for brevity)
script/spec:1: undefined method `script' for JRuby::Commands:Class (NoMethodError)

The problem appears to be the -S and calling script/spec when executing the autospec. The 'script/spec' appears to be coming from vendor/plugins/rspec_on_rails/lib/autotest/rails_rspec.rb

class Autotest::RailsRspec < Autotest::Rspec

def spec_command
"script/spec"
end

end

I greped around ZenTest and could not figure how a -S is being added for JRuby. If you manually change rails_rspec.rb to "spec" (sans the "script/") the autospec execution runs farther, but died on another error:

/home/zinger/devel/src/java/jruby/jruby-1.1.6/bin/jruby -S spec -O spec/spec.opts spec/controllers/deploys_controller_spec.rb. . ..(test list omitted for brevity)
/home/zinger/devel/src/java/jruby/jruby-1.1.6/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:442:in `load_missing_constant': uninitialized constant Spec::VERSION::BUILD_TIME_UTC (NameError)

that is all the steam I have, hope it helps

This was fixed along with JRUBY-3256. There could be other issues with autotest/ZenTest, but not because of -S (I ran through the steps described and did not get a stack to show up either).

If OP still wants autotest to work with JRuby, I worked on it a while ago: http://github.com/BanzaiMan/zentest-jruby

The patch has not been taken upstream, since Ryan Davis is planning an overhaul in some parts, apparently.