@Override
    public void startPrefixMapping(String prefix, String uri)
            throws SAXException {
        if (startsWithComposingChar(prefix)) {
            warn("Namespace prefix \u201C " + prefix
                    + "\u201D starts with a composing character.");
        }
        if (startsWithComposingChar(uri)) {
            warn("Namespace URI \u201C " + uri
                    + "\u201D starts with a composing character.");
        }
    }
@see nu.validator.checker.Checker#startPrefixMapping(java.lang.String, java.lang.String)
src/nu/validator/checker/NormalizationChecker.java