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.