Grails integration with Micronaut Data is quite a bit more complex than Spring Data and lacks detailed documentation and examples, and it is often easy to confuse several libraries related to Hibernate JPA. micronaut-hibernate-jpa micronaut-hibernate-jpa-spring micronaut-data-hibernate-jpa micronaut-data-spring I have a simple project that is not running successfully after upgrading to Micronaut 4.