As Ales mentions, although its recommended to use jboss-classloading.xml in AS5, using jboss-app.xml should perfectly work fine too. anonymous wrote : | I've been working on migration from jboss as4 to jboss as5 and hit the as5 specific classloading problem with my ejb's where the third party jars referenced by ejbs are not loaded because they are also found in the server's top level lib directory and the server is loading those (example trove.jar) rather than ones that are part of the application. Where exactly are those jars placed? You can place such thirdparty jars in EAR/lib folder and use the jboss-app.xml to isolate/scope the classloaders (as you did in AS-4.x). anonymous wrote : I know we had some issues, dunno how much Jaikiran tested it. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4247387#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...