} // -- void write( OutputStream, CoreExtensions )

    /**
     * Method writeCoreExtension.
     *
     * @param coreExtension a coreExtension object.
     * @param serializer a serializer object.
     * @param tagName a tagName object.
     * @throws IOException IOException if any.
     */
    private void writeCoreExtension(CoreExtension coreExtension, String tagName, XmlSerializer serializer)