Micronaut Data 4 / JPA question

[ethanhere]

One of our micronaut 3 application has application.yml:
jpa:
default:
packages-to-scan:
- 'myapp.entities'

With micronaut 4 I got an test error:
[ERROR] DaoTest » BeanInstantiation Bean definition [org.hibernate.SessionFactory] could not be loaded: Error instantiating bean of type [org.hibernate.boot.SessionFactoryBuilder]

Message: Entities not found for JPA configuration: 'default' within packages ['myapp.entities']. Check that you have correctly specified a package containing JPA entities within the "jpa.default.entity-scan.packages" property in your application configuration and that those entities are either compiled with Micronaut or a build time index produced with @introspected(packages="foo.bar", includedAnnotations=Entity.class) declared on your Application class
Path Taken: SessionFactoryPerDataSourceFactory.buildHibernateSessionFactoryBuilder(SessionFactoryBuilder sessionFactoryBuilder) --> SessionFactoryPerDataSourceFactory.buildHibernateSessionFactoryBuilder([SessionFactoryBuilder sessionFactoryBuilder]) --> SessionFactoryPerDataSourceFactory.buildHibernateSessionFactoryBuilder([Metadata metadata],JpaConfiguration jpaConfiguration,String name)

So according to https://micronaut-projects.github.io/micronaut-data/4.6.0/guide/index.html
application configuration file should look like
jpa:
default:
entity-scan:
packages: 'myapp.entities'

In the project there is a @entity class located in package 'myapp.entities', so I changed application.yml to
jpa:
default:
entity-scan:
packages: 'myapp.entities'

I also changed my @MicronautTest code to
@MicronautTest
@introspected(packages="myapp.entities", includedAnnotations=Entity.class)
public class DaoTest {
...

But it still doesn’t work, and the error message is the same. How can I fix that? Do you have any detailed documentation, especially explaining how to migrate micronaut data 3 to 4?

Thanks,
Ethan

[radovanradic]

It would help if you can share your example project, something might be missing in the build file.

[ethanhere]

@radovanradic thanks for responding. it's a bit complicated to share my company's source code. how can I generate a Micronaut Data 4 project with hibernate jpa and see if I can reproduce it?

Another question is that, in the long error message, I may not understand accurately on "a build time index produced with @introspected(packages="foo.bar", includedAnnotations=Entity.class) declared on your Application class" part.
In my original post, I added @introspected annotation to @MicronautTest class:
@MicronautTest
@introspected(packages="myapp.entities", includedAnnotations=Entity.class)
public class DaoTest {

Is that the right syntax to trigger micronaut 4 annotation processor to scan javax.persistence.Entity.class under myapp.entities package?

According to https://micronaut-projects.github.io/micronaut-liquibase/latest/guide/, at 4 Configuration section, it suggests to have application.yml configured as:
jpa:
default:
packages-to-scan:
- 'example.micronaut'
properties:
hibernate:
hbm2ddl:
auto: none
show_sql: true

However, the error message references configuration jpa.default.entity-scan.packages (this also appears in https://micronaut-projects.github.io/micronaut-data/4.6.0/guide/index.html). Can someone clarify what should be the right configuration? Or both are correct but different usages?

[radovanradic]

Try Micronaut Launch, this link will have predefined data-jpa and h2 feature for simple use case.
Adding @Entity should be enough, if you can try fresh example from the Micronaut Launch then it should work.

[sbscomp]

@radovanradic I've got the exact same problem as @ethanhere, but a project that's basic enough I was able to create a sample project. I created a sample project in Micronaut Launch, manually created a minimal scenario that matches my project, and it works. Copied over my controller, repository, entity, and everything works exactly as expected. I pared down my work project all the way down so it's an exact replica of the micronaut launch project, and I get the introspection error as Ethan does. The only difference between the two at this point is that my work project was generated by IntelliJ with Java 17 and Micronaut 4.3.0 as the original configuration, and I manually updated to Java 21 & Micronaut 4.3.2 by manually changing the build.gradle.kts file. I have absolutely no clue why that would be a problem, but it is, and it's enough to drive someone bonkers.

FWIW, I re-generated a new project with 4.3.2 from IntelliJ, and copied everything over, and it also works as expected.

I'm happy to share the two projects privately if it helps to identify where this issue is coming from, but whatever is going on here, it feels like there's an issue with any scenario where the project started from an earlier version and has been updated to 4.3.2 by changing the gradle build files, in such a way that it is not readily identifiable to a casual observation. If that's truly the case, this is going to end up being a massive problem for any legacy projects that want to upgrade to 4.3.2.

[ethanhere]

I solved the problem by changing javax.persistence.Entity to jakarta.persistence.Entity. In fact I changed every javax.persistence.* to jakarta.persistence.*; dependency wise changed javax.persistence-api to jakarta.persistence-api
I also added

io.micronaut.data
micronaut-data-tx-hibernate

After this change the original issue is resolved. In that maven module, the first test passed. The second test still complains:
Message: No bean of type [jakarta.persistence.EntityManager] exists.

Where can I find jakarta.persistence.EntityManager related artifacts?

[radovanradic]

Do you have dependency io.micronaut.sql:micronaut-jdbc-hikari
It's referred in this guide, maybe that guide could be helpful.

[ethanhere]

micronaut4xp-entitymanager-nobean.zip
Hi @radovanradic
Attached is a project that I stripped as much as from my work project and preserve the " No bean of type [jakarta.persistence.EntityManager] exists" error. Can you please take a look? I checked the project with the guide on dependencies, etc. but it still keeps getting " No bean of type [jakarta.persistence.EntityManager] exists" error

[radovanradic]

Mn4 uses hibernate6. Try changing this hibernate dependency in Maven

<dependency>
            <groupId>org.hibernate.orm</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>6.4.4.Final</version>
            <exclusions>
                <exclusion>
                    <groupId>org.jboss.logging</groupId>
                    <artifactId>jboss-logging</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.glassfish.jaxb</groupId>
                    <artifactId>jaxb-runtime</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

Had errors without annotations and bytebuddy so I removed those exclusions, not sure if that will be an issue for you.

[ethanhere]

Thanks @radovanradic , that works!
just curious, how did you find that out? with the version (5.6.15.Final), was the EntityManager implementation missing?

[radovanradic]

I have seen javax.persistence in the dependencies and then noticed 5.6.15 org.hibernate and figured out it should switch to hibernate6.

[ethanhere]

thanks