In our environment we are trying to make public services available to users outside our development environment. Just before we store users data, we validate the data using Java Bean Validation (JBV). At this time it is my understanding that we are best off only using Annotation Constraints on our code instead of XML (like the sample you created above) so our users will have better knowledge what to expect when interfacing our APIs for eventual database storage.

If my understanding is incorrect, please correct me so I can use this (XML) technology.