XOM API for Processing XML with Java

[Laurent Bihanic <laurent.bihanic AT atosorigin.com>]

Hi,

It is not possible to retrieve the default namespace URI using 
getNamespaceURI("") if the current element has at least one attribute not 
belong to any namespace.

The test case is the following:
<b xmlns="urn:x-xom:b" id="b">
   <c:c xmlns:c="urn:x-xom:c" id="c" />
</b>

Invoking getNamespaceURI("") on element "b" returns "urn:x-xom:b" but invoking 
getNamespaceURI("") on element "c" returns "".

The problem lies in getLocalNamespaceURI() while scanning attribute 
namespaces. This method should makes a special case for the empty prefix and 
avoid checking attribute namespaces in this case.

Another problem is the way to handle null prefixes. XOM is not consistent here 
as some methods check against null prefixes and assume "" 
(Namespaces.remove()) while others (getLocalNamespaceURI()) do not check and 
throw NullPointerExceptions.

Laurent