Prettify XML in org.w3c.dom.Document to file

[altonmint]

I have a \[code\]org.w3c.dom.Document\[/code\] (not \[code\]org.jdom.Document\[/code\]) and want to automatically format it nicely and print it into a file. How can I do that? I tried this, but it doesn't work if there are additional newlines in the document:\[code\]import java.io.ByteArrayInputStream;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.transform.OutputKeys;import javax.xml.transform.Transformer;import javax.xml.transform.TransformerFactory;import javax.xml.transform.dom.DOMSource;import javax.xml.transform.stream.StreamResult;import org.w3c.dom.Document;public class Main { public static void main(String[] args) { try { String input = "<asdf>\n\n<a>text</a></asdf>"; Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(new ByteArrayInputStream(input.getBytes())); System.out.println("-- input -------------------\n" + input + "\n----------------------------"); System.out.println("-- output ------------------"); prettify(doc); System.out.println("----------------------------"); } catch (Exception e) {} } public static void prettify(Document doc) { try { TransformerFactory transformerFactory = TransformerFactory.newInstance(); Transformer transformer = transformerFactory.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", "2"); transformer.transform(new DOMSource(doc), new StreamResult(System.out)); } catch (Exception e) {} }}\[/code\]I have directed the ouput to \[code\]System.out\[/code\] so that you can run it easily wherever you want (for instance on Ideone.com). You can see, that the output is not pretty. If I remove the \[code\]\n\n\[/code\] from the input string, everything is fine. And the document usually doesn't come from a string, but from a file and gets modified heavily before I want to prettify it. This Transformer seems to be the right way, but I am missing something. Can you tell me, what I am doing wrong?SSCCE output:\[code\]-- input -------------------<asdf><a>text</a></asdf>------------------------------ output ------------------<?xml version="1.0" encoding="UTF-8" standalone="no"?><asdf><a>text</a></asdf>----------------------------\[/code\]Expected output:\[code\]-- input -------------------<asdf><a>text</a></asdf>------------------------------ output ------------------<?xml version="1.0" encoding="UTF-8" standalone="no"?><asdf> <a>text</a></asdf>----------------------------\[/code\]