Validating data is a common task that is copied in many different layers of an application, from the presentation tier to the persistence layer. Many times the exact same validations will have to be implemented in each separate validation framework, proving time consuming and error-prone. To prevent having to re-implement these validations at each layer, many developers will bundle validations directly into their classes, cluttering them with copied validation code that is, in fact, meta-data about the class itself.

This JSR will define a meta-data model and API for JavaBean validation. The default meta-data source will be annotations, with the ability to override and extend the meta-data through the use of XML validation descriptors. It is expected that the common cases will be easily accomplished using the annotations, while more complex validations or context-aware validation configuration will be available in the XML validation descriptors.

The validation API developed by this JSR will not be specific to any one tier or programming model. It will specifically not be tied to either the web tier or the persistence tier, and will be available for both server-side application programming, as well as rich client Swing application developers. This API is seen as a general extension to the JavaBeans object model, and as such is expected to be used as a core component in other specifications, such as JSF, JPA, and Bean Binding.