What is the shortest way to pretty print a org.w3c.dom.Document to stdout?

What is the easiest way to pretty print (a.k.a. formatted) a org.w3c.dom.Document to stdout?

Call printDocument(doc, System.out), where that method looks like this:

public static void printDocument(Document doc, OutputStream out) throws IOException, TransformerException {
    TransformerFactory tf = TransformerFactory.newInstance();
    Transformer transformer = tf.newTransformer();
    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
    transformer.setOutputProperty(OutputKeys.METHOD, "xml");
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
    transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
    transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");

    transformer.transform(new DOMSource(doc), 
         new StreamResult(new OutputStreamWriter(out, "UTF-8")));
}

(The indent-amount is optional, and might not work with your particular configuration)

How about:

OutputFormat format = new OutputFormat(doc);
format.setIndenting(true);
XMLSerializer serializer = new XMLSerializer(System.out, format);
serializer.serialize(doc);

Try jcabi-xml with one liner:

String xml = new XMLDocument(document).toString();

This is the dependency you need:

<dependency>
  <groupId>com.jcabi</groupId>
  <artifactId>jcabi-xml</artifactId>
  <version>0.14</version>
</dependency>

private void printNode(Node rootNode, String spacer) {
	System.out.println(spacer + rootNode.getNodeName() + " -> " + rootNode.getNodeValue());
	NodeList nl = rootNode.getChildNodes();
	for (int i = 0; i < nl.getLength(); i++)
		printNode(nl.item(i), spacer + "   ");
}

This will return a nicely formated output by using recursive descent/ascent.

private static boolean skipNL;
private static String printXML(Node rootNode) {
	String tab = "";
	skipNL = false;
	return(printXML(rootNode, tab));
}
private static String printXML(Node rootNode, String tab) {
	String print = "";
	if(rootNode.getNodeType()==Node.ELEMENT_NODE) {
		print += "\n"+tab+"<"+rootNode.getNodeName()+">";
	}
	NodeList nl = rootNode.getChildNodes();
	if(nl.getLength()>0) {
		for (int i = 0; i < nl.getLength(); i++) {
			print += printXML(nl.item(i), tab+"  ");	// \t
		}
	} else {
		if(rootNode.getNodeValue()!=null) {
			print = rootNode.getNodeValue();
		}
		skipNL = true;
	}
	if(rootNode.getNodeType()==Node.ELEMENT_NODE) {
		if(!skipNL) {
			print += "\n"+tab;
		}
		skipNL = false;
		print += "</"+rootNode.getNodeName()+">";
	}
	return(print);
}

if you use dom4j, it would be dom4JDOM.asString()