Marko Bekhta ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HV-1949 ( https://hibernate.atlassian.net/browse/HV-1949?atlOrigin=eyJpIjoiZTQ3NGMw... ) Re: Nondeterministic behavior of HibernateValidator (in springboot?) when both annotation and xml-based definition are used ( https://hibernate.atlassian.net/browse/HV-1949?atlOrigin=eyJpIjoiZTQ3NGMw... ) Hey Martin, thanks for getting back with your experiments. I’ve looked at your various fix branches – https://github.com/alfonz19/validator-fail-mwe/compare/fixC#diff-4703104a... this one is good you only need to remove the XML files to make it work. You have correctly added a mapping here: ConstraintMapping constraintMapping = hvc.createConstraintMapping(); constraintMapping.type( mwe.validatorfail.dto.SampleDTO.class ) // instead of an XML .getter( "uuid" ) .constraint( new GenericConstraintDef<>(AnyUuid.class) ) .constraint( new NotNullDef() ); hvc.addMapping(constraintMapping); But since the XML files are still present – the constraints for mwe.validatorfail.dto.SampleDTO are coming from multiple places (including XML) and that leads to problems. So give this fixC a try and remove the validation.xml , validation-constraints.xml files. as for (3) yeah … I’ve been thinking about this one. If a constraint validator is loaded via service loader, then trying to do something about it with programmatic mappings doesn’t work since HV considers both explicit programmatic mappings and service-loaded validators as the “same programmatic definitions”. What bugs me here is that if that's so – there’s no way to override whatever comes from service loader… I’ll think about it of maybe we should change that. ( https://hibernate.atlassian.net/browse/HV-1949#add-comment?atlOrigin=eyJp... ) Add Comment ( https://hibernate.atlassian.net/browse/HV-1949#add-comment?atlOrigin=eyJp... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100225- sha1:2b972a1 )