create xml in java

createXml.java

		try {
			final ByteArrayOutputStream bos = new ByteArrayOutputStream();
			final XMLStreamWriter writer = XMLOutputFactory.newInstance().createXMLStreamWriter(bos);
			writer.writeStartDocument("UTF-8", "1.0");
			writer.writeStartElement("a");
			writer.writeDefaultNamespace(NS);
			writer.writeStartElement("b");
			writer.writeStartElement("c");
			writer.writeCharacters("d");
			writer.writeEndElement();
			writer.writeStartElement("e");
			writer.writeStartElement("f");
			writer.writeCharacters("g");
			writer.writeEndElement();
			writer.writeEndElement();
			writer.writeEndElement();
			writer.writeEndElement();
			//System.out.println(new String(bos.toByteArray(), StandardCharsets.UTF_8));
			return new ByteArrayInputStream(bos.toByteArray());
		} catch (Exception e) {
			throw new RuntimeException(e);
		}

		try {
			final Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
			final Node policyClause = doc
					.appendChild(doc.createElementNS(NS, "a"))
					.appendChild(doc.createElementNS(NS, "b"));
			policyClause
					.appendChild(doc.createElementNS(NS, "c"))
					.setTextContent("d");
			policyClause
					.appendChild(doc.createElementNS(NS, "e"))
					.appendChild(doc.createElementNS(NS, "f"))
					.setTextContent("g");
			final ByteArrayOutputStream bos = new ByteArrayOutputStream();
			TransformerFactory.newInstance().newTransformer().transform(new DOMSource(doc), new StreamResult(bos));
			//System.out.println(new String(bos.toByteArray(), StandardCharsets.UTF_8));
			return new ByteArrayInputStream(bos.toByteArray());
		} catch (Exception e) {
			throw new RuntimeException(e);
		}