ANT_17_BRANCH/src/etc/testcases/taskdefs/classloader.xml

<project name="classloader-test" default="main" basedir=".">

  <target name="init">

    <path id="myJars" >
      <!-- both ant-junit.jar and junit.jar must be loaded from the same path -->
      <pathelement path="${ant.home}/lib/ant-junit.jar" />
      <pathelement path="${junit.jar}" />
    </path>

    <classloader classpathRef="myJars" 
                 reverse="true" >
      
    </classloader>
    <junit />
  
  </target>

  <target name="main" depends="init">
    <echo message="Found JUNIT" />
  </target>

</project>