XML external entity references

[Mukul Gandhi <gandhi.mukul@gmail.com>]

Hi all,
   Say I have following XML file,

<x>
  &message;
</x>

Is it correct, that this is not a legal XML file (since an external
entity &message; is referenced and there is no <!DOCTYPE declaration)?

When I try to parse this XML with Xerces-J, I get an error message,
"[Fatal Error] test.xml:2:12: The entity "message" was referenced, but
not declared."

But the XML specification (http://www.w3.org/TR/REC-xml/) mentions
following productions:

document	   ::=   	 prolog element Misc*

prolog	   ::=   	 XMLDecl? Misc* (doctypedecl Misc*)?

doctypedecl	   ::=   	'<!DOCTYPE' S Name (S ExternalID)? S? ('['
intSubset ']' S?)? '>'

These productions imply that doctypedecl is optional. So, shouldn't
the above XML be a legal XML? Can somebody please point to the
relevant section of the XML spec, where the above XML proves to be
illegal.

Can I anyhow successfully parse the above XML? for e.g., using a
custom entity resolver, or using a catalog file.


-- 
Regards,
Mukul Gandhi