Open source XML instance diff tool

Dear colleagues,

I am looking for a decent open source diff tool for XML instance documents. I realize this has come up before but I did not find anything that I could use in the archives.

The ideal tool would have:

• Java library
• A liberal open source license that allows royalty-free redistribution
• Active development
• Ability to compare two XML instance documents and give a set of differences where each difference identifies the XPATH to element or attribute that is different
• Namespace awareness
  

Thank you for sharing any epxerience with such a tool

-- 
Regards,
Farrukh

Web: http://www.wellfleetsoftware.com