11.6.3. Validation Constraints About Validation Constraints

Validation constraints are rules applied to a java element, such as a field, property or bean. A constraint will usually have a set of attributes used to set its limits. There are predefined constraints, and custom ones can be created. Each constraint is expressed in the form of an annotation.
The built-in validation constraints for Hibernate Validator are listed here: Section, “Hibernate Validator Constraints”