Ola's App Engine project - Is it possible to update Netbeans to JRuby 1.20/Rails 2.3?

I was trying to get Ola’s App Engine “yarbl” sample running in Netbeans
which comes bundled with JRuby 1.1.4 and Ruby on Rails 2.0.2 running on
Glassfish version 3.

Since Ola’s project requires the latest version of JRuby, I tried to
configure Netbeans to use JRuby 1.20 to run the “yarbl” project.

Whenever I ran the project, Netbeans fell back to using the default
JRuby 1.1.4 instead of 1.20. This seems to be because Glassfish works
with its bundled JRuby 1.1.4.

If anyone has been able to get “yarbl” working on Windows:

If not Nebeans, which IDE are you using for local development and
If not Glassfish, which Java application server are you using for

You should use the App Engine dev_appserver to run an App Engine app
locally. I don’t know about Netbeans, but I was able to get yarbl
in eclipse:
Download yarbl and run [jruby -S warble] (you’ll need to install the
gem if you don’t have it). I had to create a “log” directory for warbler
When it’s done it will leave a directory called “war” in tmp, which is
dev_appserver needs.

If you don’t have it, install the App Engine plugin for Eclipse:

Now create a new Web Application Project. Make up some package name for
and uncheck the box to use GWT.
If you look at this project you’ll see it has a war directory. Copy all
files from yarbl/tmp/war into the eclipse war directory. I also had to
delete the indexes xml file from war/WEB-INF before the app would run.
After you’ve done this, you can select your project and do Run As →

You can now work within the war folder, although things are a bit inside
from your typical rails app. All the files that are normally in public/
in war/.
All your code is in war/WEB-INF

You’ll probably also want to install the RDT:

– Ryan B.


I got it working thanks to your excellent instructions. Thanks so much
spelling everything out in detail. The dummies approach is exactly what
needed (i.e. creating the ‘log’ directory and deleting the
database_indexes.xml in the WEB-INF folder).

Not sure if you have encountered any problems with warble. Since you
mention it, I thought I should. Although it worked eventually, various
errors appeared randomly and then went away:

cp tmp tmp/war/WEB-INF/tmp
rake aborted!
Permission denied - Permission denied - tmp
C:/JRuby120/bin/…/lib/ruby/1.8/fileutils.rb:1261:in `open’
(See full trace by running task with --trace)

The other one was:

mkdir -p tmp/war/WEB-INF
jar cf yarbl.war -C tmp/war .
rake aborted!
private method split' called for nil:NilClass C:/JRuby120/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake/repaired_system.rb: 109:infind_runnable’

Not sure if I should be worried about that for the future but warble’s
behavior does seem unpredictable. I tried two ways of invoking it. The

  • as you suggested - was “jruby -S warble”. The second was to install
    ruby gem (not JRuby gem) and invoke simply as “warble” inside the yarbl
    folder. In both cases I got the errors listed above. And then
    subsequently I
    didn’t get them any more after repeating the command several times. Very

Anyway, you made my day, Ryan. I had been struggling to figure out why I
couldn’t get it working in Netbeans.

Thanks! I’m excited about getting some code up on App Engine. This is