Jruby Gems-in-a-jar issue

Question

Hi all, I am trying to write some code in ruby (using jruby) to be compiled to java bytecode with jrubyc and deployed to a remote machine where it will be run on the JVM (no ruby available there).

Everything works fine as long as I am happy to stick with the standard jruby library. As explained on the jruby website, I simply copy the jruby-complete.jar library to the remote machine and include it in the classpath at runtime. I fire my compiled script and it works: cool!

The problems start when I need some other libraries (typically rubygems) to run my script.
I am aware of cool stuff like rawr, -which I successfully tested- to put together all you need in a single package. However that is not the solution I am looking for: I will have many small scripts to run independently and I don't want each of them to grow to at least 10 MB just because I insanely include the jruby-complete.jar in each of them.

What I would like is to compile a .jar for each of the libraries that I will need to use, put all of them in a common folder on the remote machine and include them at runtime in the classpath when I run my compiled jruby scripts on the JVM.
This said, I tried to follow the instructions here: http://blog.nicksieger.com/articles/2009/01/10/jruby-1-1-6-gems-in-a-jar
I tried exactly the example shown there, with the "chronic" gem. Going step by step:

1. Install the gem locally: java -jar jruby-complete-1.1.6.jar -S gem install -i ./chronic chronic --no-rdoc --no-ri
2. Package it into a jar: jar cf chronic.jar -C chronic .

3. Write a two lines test script, saving it as testt.rb:

   require 'chronic'
   Chronic.parse('tomorrow')

4. Compile with: jrubyc testt.rb

5. Run the resulting java class testt.class with the following (having both jruby-complete.jar and chronic.jar in the same folder as the java class): java -cp .:/jruby-complete.jar:./chronic.jar testt

I get the following error:

Exception in thread "main" file:/Users/ave2/NetBeansProjects/jrubywatir/lib/jruby-complete.jar!/METAINF/jruby.home/lib/ruby/site_ruby/shared/builtin/core_ext/symbol.rb:1:in `const_missing': uninitialized constant Chronic (NameError)
from testt.rb:2
...internal jruby stack elided...
from Module.const_missing(testt.rb:2)
from (unknown).(unknown)(:1)

I really don't understand what I am doing wrong, and I am totally stuck on this. I am a noob in Ruby, much more used to Python: don't miss a chance to convert an infidel! :-) Thanks.

Answer 1

Put this at the top of your test script:

require 'rubygems'

Answer 2

From what I can tell, it looks like you're not doing anything wrong, and you've probably hit a bug. Can you try your example with a more recent release (http://jruby.org/download) and if you still see the issue, create a bug at http://bugs.jruby.org/ ? Thanks.