org.jboss.naming.ExternalContext.SerializableInitialContext exists in server/default/lib/jboss.jar but it does not exist for a client that uses [jboss]/client/jbossall-client.jar.
As a result if a client app needs to lookup an ExternalContext on a remote JBoss instance, the client must enable RMI classloader or include server/default/lib/jboss.jar
It would be nicer if ExternalContext was included with jbossall-client.jar