We have seen how to incorporate JSR-303 Bean Validation with Spring MVC. In addition to Bean Validation, Spring has its own classic mechanism to perform validation as well, which is called Spring vValidation. The JSR-303 Bean Validation is much more elegant, expressive, and, in general, simpler to use when compared to the classic Spring validation. But the classic Spring validation is very flexible and extensible. For example, consider a cross field validation where we want to compare two or more fields to see whether their values can be considered as valid in combination. In such a case we can use Spring validation.

In the last section, using JSR-303 Bean Validation we have validated some of the individual fields on our Product domain object; we haven't done any validation that combines one or more fields. We don't know whether the combination of different fields makes sense.