ant target for running cucumber

cuke4.output

cuke4:
     [java] Gem::LoadError: Could not find RubyGem cucumber (>= 0)
     [java] 
     [java]   report_activate_error at /Users/gdinwiddie/jruby-1.6.2/lib/ruby/site_ruby/1.8/rubygems.rb:861
     [java]                activate at /Users/gdinwiddie/jruby-1.6.2/lib/ruby/site_ruby/1.8/rubygems.rb:255
     [java]                     gem at /Users/gdinwiddie/jruby-1.6.2/lib/ruby/site_ruby/1.8/rubygems.rb:1215
     [java]                  (root) at /Users/gdinwiddie/jruby-1.6.2/bin/cucumber:18

cuke4.xml

  <target name="cuke4" description="Run the cucumber tests">
    <java classname="org.jruby.Main" fork="true" failonerror="true">
      <classpath>
        <fileset dir="${jruby.home}/lib">
          <include name="*.jar"/><!-- finds 'jruby' -->
          <include name="**/*.rb" /><!-- doesn't help -->
        </fileset>
        <pathelement location="${jruby.home}/lib/ruby/site_ruby/1.8"/><!-- finds 'rubygems' -->
        <pathelement location="${jruby.home}/lib/ruby/gems/**/lib"/><!-- doesn't help -->
        <pathelement location="${jruby.home}/lib/ruby/gems/1.8/gems/cucumber-1.0.0/lib"/><!-- doesn't help -->
        <pathelement location="${jruby.home}/lib/ruby/gems/1.8/gems"/><!-- doesn't help -->
        <pathelement location="${jruby.home}/lib/ruby/gems/1.8"/><!-- doesn't help -->
        <pathelement location="${jruby.home}/lib"/><!-- doesn't help -->
      </classpath>
      <arg value="-S"/>
      <arg value="${jruby.home}/bin/cucumber"/>
    </java>
  </target>

gempath.output

gempath:
     [java] NameError: uninitialized constant Gem
     [java]   const_missing at org/jruby/RubyModule.java:2569
     [java]          (root) at -e:1

gempath.xml

  <target name="gempath" description="display the gem path">
    <java classname="org.jruby.Main" fork="true" failonerror="true">
      <classpath>
        <fileset dir="${jruby.home}/lib">
          <include name="*.jar"/>
        </fileset>
        <pathelement location="${jruby.home}/lib/ruby/site_ruby/1.8"/><!-- finds 'rubygems' -->
      </classpath>
      <arg value="-e"/>
      <arg value="puts Gem.path"/>
    </java>
  </target>

Note: I started with the simple and obvious:

<target name="cuke1" description="Run the cucumber tests">
    <exec executable="cucumber" >
        <env key="PATH" path="${jruby.home}/bin" />
    </exec>
</target>

but that gives me "java.lang.ClassNotFoundException: org.jruby.Main"

I went back to the simple and obvious start, and, once I found the key to reading the OS environment variables, got it working with the following:

<target name="cucumber" description="Run the cucumber tests">
    <property environment="env" />
    <exec executable="cucumber" >
        <env key="PATH" path="${env.PATH}:${jruby.home}/bin" />
        <env key="CLASSPATH" file="${jruby.home}/lib/jruby.jar" />
    </exec>
</target>