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6.3.2. JPA If you are using JPA 2 and Hibernate Validator is in the classpath the JPA2 specification requires that Bean Validation gets enabled. The properties javax.persistence.validation.group.pre-persist, javax.persistence.validation.group.pre-update and javax.persistence.validation.group.pre-remove as described in Section 6.3.1, “Hibernate event-based validation” can in this case be configured in persistence.xml. persistence.xml also defines a node validation-mode while can be set to AUTO, CALLBACK, NONE. The default is AUTO. In a JPA 1 you will have to create and register Hibernate Validator yourself. In case you are using Hibernate EntityManager you can add a customized version of the BeanValidationEventListener described in Section 6.3.1, “Hibernate event-based validation” to your project and register it manually.