The existing method DocPrintJob.getAttributes() declares that
        it returns AttributeSet. But this set will only contain
        PrintJobAttribute instances, so is really a PrintJobAttributeSet,
        which is an extension of the AttributeSet interface.
        and that is what the implementations in fact create and return.
        The API was less restrictive to permit the return of a request
        set before job submission, but the API evolved since then to
        supply the request set only at submission time. So this is now out
        of date and the getAttributes method needs to be corrected.