Jackson (http://jackson.codehaus.org/)
Skaringa (http://skaringa.sourceforge.net/)
If JSON-Java is there, aren't you finding yourself thinking about XML-JSON conversions. Yes you can enjoy reading and example at http://www.thomasfrank.se/xml_to_json.html
Suerly, there are other tools for the same purpose which are budding.
Particularly interesting are the tools coming up that aims to achieve what has been done with XML for a long time, i.e XSLT. Go on with some reading at the links below and you will find them interesting.
http://goessner.net/articles/jsont/ (XML: XSLT :: JSON : -----)
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