I found JBossXBDeployerHelper assumes DefaultSchemaResolver private static DefaultSchemaResolver resolver = (DefaultSchemaResolver)SingletonSchemaResolverFactory.getInstance().getSchemaBindingResolver(); This became a problem with XB 2.0.1.Beta2 where I changed the default schema resolver to MultiClassSchemaResolver (which does not extend DefaultSchemaResolver). The difference between the two resolvers is that MultiClassSchemaResolver allows to map more than one class to a namespace (useful for our JCA metadata, for example). The reason I didn't want to implement this in DefaultSchemaResolver is that its removeClassBinding(ns) method returns a single class (in MultiClassSchemaResolver it returns an array). Maybe, we can agree on an interface like SchemaResolverWithURIToClassMapping? Or other suggestions? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4215255#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...