I did some research. Mainly I read http://www.ibm.com/developerworks/library/x-android/
Android supports SAX parser (as Flow already mentioned), DOM parsing and XmlPullParser.
The article says a StAX parser is more efficient because it does not read the whole XML and reading can therefore be finished, if you are done. But that probably isn't significant.
I guess, if you want to do it right, you would use SAX parser to read XML and use DocumentBuilderFactory (DOM) to write XML.
This would work for Android and non-Android Java and would get rid of the extra dependency (org.xmlpull).
But it would also mean a complete rewrite...
So, probably a bad option.
