More information about JBoss classloader and Isolation of EAR archives you can find on JBoss wiki pages: http://www.jboss.org/wiki/Wiki.jsp?page=ClassLoadingConfiguration
and: http://www.jboss.org/wiki/Wiki.jsp?page=JBossClassLoadingUseCases gives you detalied scenarios which may explain you a lot how to configure JBoss.
Janusz: Many thanks for your reply and the references. I have carefully read the latter and followed them scrupulously, and I am still getting "bleeding" of classes. I have returned to using Axis as a directly deployed WAR file and used the jboss-web.xml file to configure scoped classloading exactly as shown. However, Axis is still able to load classes belonging to the unified classloader, even though I set Java2ParentDelegation of the scoped repository to false. As I understand it, that should be impossible. I don't know what else to do. I have worked with J2EE for years, and am proficient with at least four app servers other than JBoss--I've simply never come up against a problem this intractable. Of course, I may just be being an idiot. That, too, has happened before.