Adding linebreak in xml file before root node

Question

I am trying to add line break after my comments above the root node in XML document.

I need something like this:

Answer 1

Revisiting this after some time because I had the same issue. I found another solution that does not need to buffer the output in a String:

1. Write only the XML-declaration by passing an empty document. This will also append a linebreak.

2. Write the document content without XML-declaration

Code:

StreamResult streamResult = new StreamResult(writer);
// output XML declaration with an empty document
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
transformer.transform(new DOMSource(), streamResult);
// output the document without XML declaration
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.transform(new DOMSource(doc), streamResult);