How to remove the empty lines in the generated XML?

Question

Hi, XML/JDOM experts,
I used JDOM to generate an XML file in my exercise of comparing two xml files.
I used a lot of times addContent()...
The resuting xml is fine for its contents.
But I don't like so many empty lines (or carriage return).
Would you help to refine the result?
Best regards,
AG
Sample results:
<li delta:property="Modified">
<code delta:property="Modified">
<delta:NewValue>foreignObject</delta:NewValue>
<delta:OldValue>text</delta:OldValue>
</code>
<svg xmlns="http://www.w3.org/2000/svg" width="6cm" height="45px" delta:property="Removed">
<rect y="0" x="27px" width="110px" height="45px" style="fill: #C1FFFF" />
<foreignObject width="120px" y="0" x="20px">
<div xmlns="http://www.w3.org/1999/xhtml">
<ul>
<li>First item</li>
<li>Second item</li>
</ul>
</div>
</foreignObject>
</svg>
<svg xmlns="http://www.w3.org/2000/svg" width="9.5cm" height="1.2cm" delta:property="Added">
<text y="33px" x="13px" style="font-family: helvetica; font-size: 14pt; fill: #FFAA00">A simple
text in SVG
</text>
</svg>
</li>

Answer 1

The solution is to add
outputter.setTrimAllWhite(true);
Below is the sample code.
     FileOutputStream out = new FileOutputStream("delta.xml");
     XMLOutputter outputter = new XMLOutputter(" ", true, "UTF-8");
     outputter.setTrimAllWhite(true);
     outputter.output(doc1, out);
     out.close();