JSR 303 – Bean Validation

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.

http://parleys.com/display/PARLEYS/Home#title=JSR%20303%20-%20Bean%20Validation;slide=1;talk=14123052