Remove the XML header from an XML in Java

Ideally you can make an API call to exclude the XML header if desired. It doesn't appear that KXmlSerializer supports this though (skimming through the code here). If you had a org.w3c.dom.Document (or actually any other implementation of javax.xml.transform.Source) you could accomplish what you want this way:

TransformerFactory tf = TransformerFactory.newInstance();
Transformer transformer = tf.newTransformer();
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
StringWriter writer = new StringWriter();
transformer.transform(new DOMSource(doc), new StreamResult(writer));

Otherwise if you have to use KXmlSerializer it looks like you'll have to manipulate the output.

If you use a JAXP serializer you get access to all the output properties defined in XSLT, for example omit-xml-declaration="yes". You can get this in the form of an "identity transformer", called using transformerFactory.getTransformer() with no parameters, on which you then call setOutputProperty(). Another example:

TransformerFactory tf = TransformerFactory.newInstance();
Transformer t = tf.newTransformer();
t.setOutputProperty("omit-xml-declaration", "yes");