Jruby-in a jar already bundles rspec and rake, so the goal was to find out where it gets packaged.

Download the jruby source zip, extract it and open the build.xml file, search for “rspec” (there’s two occurences) and you’ll find that it’s passed in as an argument to the gem installer, add in another line with “cucumber”:

<target name="install-gems">
  <property name="jruby.home" value="${basedir}"/>
  <java classname="org.jruby.Main" fork="true" maxmemory="${jruby.launch.memory}" failonerror="true">
    <classpath refid="build.classpath"/>
    <classpath path="${jruby.classes.dir}"/>
    <sysproperty key="jruby.home" value="${jruby.home}"/>
    <arg value="--command"/>
    <arg value="maybe_install_gems"/>
    <arg value="rspec"/>
    <arg value="rake"/>
    <arg value="cucumber"/> <!-- add cucumber -->
    <arg value="--env-shebang"/>
  </java>
</target>

Then run ant:

$ ant jar-complete

To verify that everything is fine:

$ java -jar lib/jruby-complete.jar -S gem list

*** LOCAL GEMS ***

builder (2.1.2)
cucumber (0.2.3)
diff-lcs (1.1.2)
polyglot (0.2.5)
rake (0.8.4)
rspec (1.2.2)
sources (0.0.1)
term-ansicolor (1.0.3)
treetop (1.2.5)

Great we’ve now managed to package jruby-in-a-jar with some additional gems. Now to run cucumber on jruby in eclipse.