Jar urls are being created for the SynthenticDirEntryHandler types of empty directories in jars. Eventually a nested jar:jar url is being created for a jar in derbyTesting.jar: jar:jar:file:/home/svn/JBossHead/jboss-head/build/output/jboss-5.0.0.CR1/server/cts/lib/derbyTesting.jar!/org/apache/derbyTesting/functionTests/testData/v1/j1v1.jar!/META-INF/ that jar should not be in the lib dir, but we also should handling this correctly. I also don't think we should be relying on the jdk jar: url handler to deal with the jar contents. It internally relies on JarFile which is not serializable. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4133382#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...