java生成xml 空节点文档问题

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.newDocument();

Element rootEle = document.createElement("stream");
document.appendChild(rootEle);

TransformerFactory tff = TransformerFactory.newInstance();
Transformer tf = tff.newTransformer();

ByteArrayOutputStream baos = new ByteArrayOutputStream();
tf.setOutputProperty("indent", "yes");
tf.transform(new DOMSource(document), new StreamResult(baos));

结果:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<stream/>

我希望结果是
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<stream></stream>

请问该如何修改呢？我这边试了好多种办法都无法做到，知道的大神 麻烦教一下，谢谢了