Some remarks

I think an Architecture needs not just a set of component technologies
but rather also defined services with interfaces

In our case
Java --> EJB --> (Possible Filter? to map objects) --> X -->
     ---> Castor --> Y --> Oracle 9i or Flat File

Services are 
			enquire about XML objects
				do they exist, what are their children/parent/name etc.
			get XML objects (either recursively thru tree or just container)
			put XML objects (either recursively thru tree or just container)
			etc
			
1) I don't know if X or Y exists -- there is in principle some sort of
   mapping of GNDI specification to that needed by system that extracts/stores
   from file/database
   This could be a filter Y or a specification X of Castor reader
   
2) The Interface or Service is defined at Java level and is the "replacement
   of JDBC" for accessing XML objects
   It presumably should look like W3C DOM methods
   Actually I don't understand if this interface is at Java or EJB level or both

3) In practice we should use GXOS URI to access XML objects
   I was beaten up by somebody who doesn't like W3C URI. He says better to
   define as N indexable tags gndi://tag1/tag2/ .... /tagN