Yes, I've seen this Mauve testcase (which, IIRC, now fails).
Personally, I feel that copying obscure parts of Sun's implementation is
not right for GNU Classpath. The above is not documented (AFAICS) in
the specification, and only occurs in Sun's VM. In fact, the
documentation for setCurrency() suggests that null is a perfectly valid
value for the currency attribute. I haven't invented a new scheme, but
followed the spec. (and common sense) as much as possible.
getCurrency() returning null is a lot clearer than obscure "XXX" strings
getting into your programs anyway, IMO. Generally, if you want the
currency symbols, I would imagine you would ensure that they are
available.