Often applications running on Sun Java System Web Server require access to resources stored in an external JNDI repository. For example, generic Java objects could be stored in an LDAP server as per the Java schema. While a custom resource allows you to access a local JNDI repository, to access an external JNDI repository you must use an external JNDI resource. An external JNDI factory must implement the javax.naming.spi.InitialContextFactory interface.
For information on creating an external JNDI resource, see Creating External JNDI Resources.