dom.java

DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("root");
rootElement.appendChild(doc.createTextNode("A\u0000B"));
doc.appendChild(rootElement);

TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
final ByteArrayOutputStream os = new ByteArrayOutputStream();
StreamResult result = new StreamResult(os);
transformer.transform(source, result);
System.out.println(new String(os.toByteArray(), StandardCharsets.UTF_8));