Classpath definition in Maven Antrun

               ...
               <taskdef name="startBuildActivity" classname="com.ibm.team.build.ant.task.StartBuildActivityTask">
                  <classpath>
                     <fileset dir="C:\jazz\buildsystem\buildtoolkit">
                        <include name="*.jar" />
                     </fileset>
                  </classpath>
               </taskdef>
               ...

Using this example, in 3 or so executions of maven-antrun-plugin, I get this:

   [INFO] --- maven-antrun-plugin:1.7:run (rtc-process-resources-activity) @ cadam-rtc-build ---
   [INFO] Executing tasks
   
   main:
   [INFO] Executed tasks
   [INFO] 
   [INFO] --- maven-antrun-plugin:1.7:run (rtc-compile-activity) @ cadam-rtc-build ---
   [INFO] Executing tasks
   
   main:
   [ERROR] PermGen space -> [Help 1]
   [ERROR] 
   [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
   [ERROR] Re-run Maven using the -X switch to enable full debug logging.
   [ERROR] 
   [ERROR] For more information about the errors and possible solutions, please read the following articles:
   [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/OutOfMemoryError
	

I am not sure what is causing this issue, but I notice an unusually high consumption of memory by Maven's Java process before crash (~1GB for a demo "Hello World" example). Maybe something related to the way the ant task jars are declared? Any suggestions how can I fix this and reduce memory usage?