[jdom-interest] JDOM namespace bug?

[philip.nelson at omniresources.com]

> I don't understand the reason for the restriction, though.
> The namespace prefixes act as a kind of abbreviation, so
> 
> <foo:root xmlns:foo=STRING>
>   <foo:one/>
>   <foo:two/>
>   <foo:three/>
> </foo:root>
> 
> is the same as
> 
> <root xmlns=STRING>
>   <one xmlns=STRING/>
>   <two xmlns=STRING/>
>   <three xmlns=STRING/>
> </root>
> 
> Or rather, they are the same when STRING is
> any string except for the empty string, in which
> case the latter is legal but the former is not.
> 

String MUST be a URI except in the one special case of an empty namespace.
Since xmlns:ej="" implies a namespace, there has to be a uri.  We will be
doing more rather than less checking on that though we have narrowed the
idea to not require it to be a valid uri, only valid uri characters.