TypedXMLStreamWriter sw = (TypedXMLStreamWriter) of.createXMLStreamWriter(new DOMResult(doc));
sw.writeStartDocument();
sw.writeStartElement("root");
sw.writeIntAttribute(null, null, "attr", -900);
sw.writeInt(123);
sw.writeEndElement();
sw.writeEndDocument();
sw.close();
Element root = doc.getDocumentElement();