See https://community.jboss.org/message/766856#766856.
In summary need to add
<dependencies> <module name="org.apache.log4j"/> <module name="javax.api"/> </dependencies>
to modules/org/freemarker/main/module.xml
and
<dependencies> <module name="javax.api/> </dependencies>
to modules/com/thoughtworks/xstream/main/module.xml