# XML code generation - Extensions

## XML code generation extensions - Motivation

With Castor 1.2 and earlier releases it has already been possible to generate Java classes from an XML schema and use these classes for XML data binding without having to write a mapping file.

This is possible because the Castor XML code generator generated - in addition to the domain classes - a set of XML descriptor classes as well, with one descriptor class generated per generated domain class. It's this XML descriptor class that holds all the information required to map Java classes and/or field members to XML artifacts, as set out in the original XML schema definitions. This includes ....

- artefact names

- XML namespace URIs

- XML namespace prefix

- validation code

Starting with Castor 1.3, a mechanism has been added to the XML code generator that allows extension of these core offerings so that either additional content is added to the generated domain classes additonal descriptor classes are gernated.