Jing is a RELAX NG validator in Java.

This version of Jing implements

    * RELAX NG 1.0 Specification,
    * RELAX NG Compact Syntax, and
    * parts of RELAX NG DTD Compatibility, specifically checking
      of ID/IDREF/IDREFS.

Jing also has experimental support for schema languages other than
RELAX NG; specifically

    * W3C XML Schema (based on Xerces-J);
    * Schematron;
    * Namespace Routing Language.