I have a Java String that contains XML, with no line feeds or indentations. I would like to turn it into a String with nicely formatted XML. How do I do this?

String unformattedXml = "<tag><nested>hello</nested></tag>";
String formattedXml = new [UnknownClass]().format(unformattedXml);

Note: My input is a String. My output is a String.

(Basic) mock result:

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <tag>
    <nested>hello</nested>
  </tag>
</root>