Right now, passing in a ValidatorFactory via org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.withValidatorFactorry doesn't work, i.e., the ValidatorFactory that's passed in doesn't actually get used. Making the ValidatorFactory available via EntityManagerFactory.getProperties().get("javax.persistence.validation.factory") fixes this problem, i.e., the ValidatorFactory that's passed in to withValidatorFactory will actually get used.