Okay, I did some extra checks using some (remote) debugging on the JBoss AS. I added some breakpoints to org.jboss.invocation.MarshalledValueInputStream. It seems like Thread.currentThread().getContextClassLoader() does return a different classloader than ChartMetadata.getClass().getClassLoader() (and thus the classloader used to load the webapp). The first returns a org.jboss.mx.loading.UnifiedClassLoader3 instance, while the second returns a org.jboss.web.tomcat.service.WebAppClassLoader. The ChartMetadata class is packaged as part of a .war archive. The application itself is packaged in an .ear archive. Does this make the difference? Should Tomcat use the unified classloader instead? When clecking ChartMetadata.class.getClassLoader() and Thread.currentThread().getContextClassLoader() from within my code (the helper-class used to access the TreeCache) all seems to be fine (both point to the WebAppClassLoader. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4106686#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...