How to pretty print XML from Java?

Question

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?

Answer 1

In case you do not need indentation that much but a few line breaks, it could be sufficient to simply regex...

String leastPrettifiedXml = uglyXml.replaceAll("><", ">\n<");

The code is nice, not the result because of missing indentation.

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(For solutions with indentation, see other answers.)