The Apache Xerces2 parser is the reference implementation of XNI but
other parser components, configurations, and parsers can be written
using the Xerces Native Interface.

Xerces2 also provides a complete implementation of the Document Object
Model Level 3 Core and Load/Save W3C Recommendations and provides a
complete implementation of the XML Inclusions (XInclude) W3C
Recommendation.  It also provides support for OASIS XML Catalogs v1.1.

Xerces2 is able to parse documents written according to the XML 1.1
Recommendation, except that it does not yet provide an option to enable
normalization checking as described in section 2.13 of this
specification.  It also handles namespaces according to the XML
Namespaces 1.1 Recommendation, and will correctly serialize XML 1.1
documents if the DOM level 3 load/save APIs are in use.