For upgrade, when an application in jboss-4.2.2 was compiled with jdk6 and deployed to Jboss-5.1.0.GA,
jboss5.1.0.GA requires an entry for the property java.naming.provider.url=<OurJbossServerAppIPAddress>:1099
to make the application work.
When verified with our distribution of existing Jboss-4.2.2 it has the entry for provider.url.
Standard distributions of JBoss-4.2.2 or Jboss-5.1.0.GA both have only
java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces
My understanding is jndi properties file is referred by runtime
only when InitialContext is instantiated with no args constructor.
Two applications have codes to instantiate IntialContext with no args constructor.
One application works fine in Jboss-5.1.0.GA without the provider.url entry.
The second requires the provider.url.