developerWorks: The Java XML Validation API

"Validation reports whether a document adheres to the rules specified by the schema. Different parsers and tools support different schema languages such as DTDs, the W3C XML Schema Language, RELAX NG, and Schematron. Java 5™ adds a uniform validation Application Programming Interface (API) that can compare documents to schemas written in these and other languages. Learn about this XML validation API."

The Java XML Validation API