@Inject Injection into EntityListener not working

[HonoluluHenk]

Describe the bug
I do have JPA entities annotated with @EntityListeners.
I @Inject some CDI bean (@RequestScoped in my case but happens for other scopes, too) into the EntityListener.
The bean never gets injected, the reference is allways null.

Things I tried:

• placing some CDI scope annotation onto the entity listener.
• Tried different CDI scopes on the injected bean
• Tried all variants of injection: constructor-, setter- and attribute-injection on the listener

Expected behavior
Instance of the CDI bean should get injected

Actual behavior
The CDI bean reference is allways null resulting in a NPE when accessing some attribute of the bean.

To Reproduce
See attached test case

Configuration

quarkus.datasource.url=jdbc:h2:tcp://localhost/mem:test
quarkus.datasource.driver=org.h2.Driver
quarkus.hibernate-orm.database.generation=drop-and-create

(Also happens with postgresql, drop-and-create is just for testing)

Environment (please complete the following information):

• Output of java -version: from 8 to 11
• Quarkus version or git rev: 1.2.0

Additional context
Interestingly, when the CDI bean I want injected into the EntityListener ist injected somewhere else (e.g. some @ApplicationScoped bean), injection works.
Possible causse: looks like Quarkus bean discovery does not regard EntityListeners as trigger for registering some bean during compile-time-initialization.

Example code:

src/main/java/...

package org.acme;

import java.util.UUID;

import javax.persistence.Entity;
import javax.persistence.EntityListeners;
import javax.persistence.Id;
import javax.persistence.Version;

@Entity
@EntityListeners(FooListener.class)
public class FooEntity {

	@Id
	private String id = UUID.randomUUID().toString();
	@Version
	private long version;
	private String data;

	// getters/setters omitted for brevity
}

package org.acme;

import javax.enterprise.context.Dependent;
import javax.inject.Inject;
import javax.persistence.PrePersist;

// also happens with @Dependent
public class FooListener {

	@Inject
	private FooBean fooBean;

	@PrePersist
	public void prePersist(FooEntity entity) {
		entity.setData(fooBean.pleaseDoNotCrash());
	}
}

package org.acme;

import javax.enterprise.context.RequestScoped;

@RequestScoped
public class FooBean {

	public String pleaseDoNotCrash() {
		return "Yeah!";
	}
}

src/test/java/...

package org.acme;

import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.transaction.Transactional;

import io.quarkus.test.junit.QuarkusTest;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

@QuarkusTest
public class EntityListenerInjectionTest {

	@Inject
	private EntityManager em;

	@Test
	@Transactional
	public void shouldNotCrash() {
		FooEntity o = new FooEntity();
		em.persist(o);
	}

	@Test
	@Transactional
	public void shouldInvokeEntityListener() {
		FooEntity o = new FooEntity();
		em.persist(o);
		assertEquals("Yeah!", o.getData());
	}
}

package org.acme;

import io.quarkus.test.common.QuarkusTestResource;
import io.quarkus.test.h2.H2DatabaseTestResource;

@QuarkusTestResource(H2DatabaseTestResource.class)
public class TestResources {
}

[Sanne]

Support for JPA Listeners was not implemented yet; please see the limitations documented here:

• https://quarkus.io/guides/hibernate-orm#limitations

@HonoluluHenk , may I re-classify this report as a feature request?

[HonoluluHenk]

OMG, sorry for missing this :(

may I re-classify this report as a feature request?

sure!

[HonoluluHenk]

For all those arriving here via google:

A workaround is to create some other bean and @Inject your bean there... just so Quarkus knows it needs to register your bean for CDI injection.

@ApplicationScoped
public class JPAEntityListenerInjectionWorkaround {
  @Inject FooBean fooBean;
}

Then retrieve your bean instance in the EntityListener like this:
FooBean fooBean = CDI.current().select(FooBean.class).get();

[Sanne]

OMG, sorry for missing this :(

no worries at all :) I realize it's not very visible; also we could do a better job in logging a warning.

[mkueng1]

I have the same use case -> so +1 for the "user demand"

[HonoluluHenk]

See pr #7296 for possible fix/workaround

[mkouba]

@HonoluluHenk thanks for your contribution. However, I think that we should avoid adding the Fake* classes just to workaround this particular problem.

It should be fairly easy to identify entity listerners (i.e. scan the index for @PrePersist) and add a synthetic scope to them in a quarkus extension. The other step would be to provide a quarkus-specific listener "instantiator". Something similar to QuarkusConstructorInjector we use for RESTEasy.

Ideally, Hibernate should provide an SPI that can be implemented by quarkus. If I understand it correctly, Hibernate is currently using BeanManager to create listener instances. Is there a way to replace the current implementation with some pluggable mechanism?

@Sanne CC

[HonoluluHenk]

I'll have a look into it...

[Sanne]

@mkouba +1 no need for fake classes. Regarding the Hibernate SPI: to be honest I don't know this area very well, I should investigate but am a bit overwhelmed ATM.

Even if it's not possible today, it's certainly possible to change the code :) We do regular Hibernate releases to address on any Quarkus need.

@HonoluluHenk thanks! appreciate it. If you need to change any code in Hibernate ORM, feel free to take that in consideration. Ping me if you send a PR to Hibernate, I'll prioritize it. (hopefully it won't be needed?)

[knutwannheden]

@HonoluluHenk Did you get any time to look into this? I am also working on a project which would require support for entity listeners / JPA callbacks.

@Sanne Any idea when the Quarkus team will get around to look into this? Possibly we need to consider finding a workaround or contributing a solution.

[Sanne]

Any idea when the Quarkus team will get around to look into this? Possibly we need to consider finding a workaround or contributing a solution.

sorry, I don't know. It's for sure high on the wish list, but there's a couple more important things that need to be done first and it's a small team. A contribution would be great, or even if you find a reasonable workaround please describe it here for others.

[knutwannheden]

@Sanne Thanks for the heads-up.

[j-be]

@knutwannheden For completness: the workaround from #6948 (comment) works fine for me.

As a side-note: you need to inject your bean somewhere (it seems to neither matter where, nor if it is actually used there) for it to be available for programmatic lookup via CDI.current().

[knutwannheden]

@j-be The workaround you mention appears to be working for JPA entity listeners, but I don't see it working for Envers revision listeners. Explicitly injecting a revision listener instance somewhere else doesn't help with the instantiation that is required for Envers.

To my example I have now however added an @Dependent annotation to MyRevisionListener and then also inject it into MyRevisionListenerTest. But as I mentioned, the problem still remains.

Please let me know if I missed something.

Oops. I mixed this issue up with the issue #8268 I recently reported. Please disregard the comment above.

[j-be]

@knutwannheden that is weird indeed. I am using the workaround in an envers RevisionListener to accees the userId from the OAuth Cookie and save it inside the revision. What I am doing is:

• Define a @ApplicationScoped SecurityService
• @Inject all the needed stuff there
• @Inject SecurityService in one of my JaxRS classes
• Use CDI in the RevisonListener

I'm not sure whether the SecurityService in between makes a difference - I implemented it for convenience only, i.e. to have everything in one place.

Btw, how does the error manifest (Build error, NullPointer on runtime, ...)?

[knutwannheden]

@j-be Using CDI.current() in the RevisionListener should work as expected, but normally it should be possible to use @Inject in the RevisionListener implementation.

The problem is then that the @Inject annotated fields are null.

[j-be]

@knutwannheden sorry, my bad, only saw your "Oops" comment just now. Nevermind then, I didn't get @Inject to work either, but it sure would be nice to have 😃

[wicksim]

I'm a little bit confused about what should work and what shouldn't. Regarding to https://quarkus.io/guides/hibernate-orm#limitations, there is no support for JPA Calllbacks. But with 1.3.2.Final, listeners itself (e.g. a method in a @EntityListeners annotated with @PostLoad is called) seem to work in my case. The only problem seems to be the not injected bean in the listener.

Am I missing something? Is the limitation only true in native mode?

[knutwannheden]

I'm a little bit confused about what should work and what shouldn't. Regarding to https://quarkus.io/guides/hibernate-orm#limitations, there is no support for JPA Calllbacks. But with 1.3.2.Final, listeners itself (e.g. a method in a @EntityListeners annotated with @PostLoad is called) seem to work in my case. The only problem seems to be the not injected bean in the listener.

That is also what my testing confirms.

Am I missing something? Is the limitation only true in native mode?

Indeed. In native mode @EntityListeners doesn't work at all. The only thing which apparently works is if your entity class itself has methods annotated with @PrePersist, etc.

[SoftMeng]

public class JpaEntityListeners {

    @PrePersist
    public void prePersist(Object entity) {
        ReflectUtil.invoke(entity, "setCreateTime", LocalDateTime.now());
        ReflectUtil.invoke(entity, "setUpdateTime", LocalDateTime.now());
        JsonWebToken context = CDI.current().select(JsonWebToken.class).get();
        if (Objects.nonNull(context)) {
            String username = context.getClaim(Claims.preferred_username.name());
            if (Objects.nonNull(username)) {
                ReflectUtil.invoke(entity, "setCreateBy", username);
                ReflectUtil.invoke(entity, "setUpdateBy", username);
            }
        }
    }

    @PreUpdate
    public void preUpdate(Object entity) {
        ReflectUtil.invoke(entity, "setUpdateTime", LocalDateTime.now());
        JsonWebToken context = CDI.current().select(JsonWebToken.class).get();
        if (Objects.nonNull(context)) {
            String username = context.getClaim(Claims.preferred_username.name());
            if (Objects.nonNull(username)) {
                ReflectUtil.invoke(entity, "setUpdateBy", username);
            }
        }
    }
}

I use JsonWebToken context = CDI.current().select(JsonWebToken.class).get();

[famod]

@HonoluluHenk Have you ever gotten round to looking into this?

[HonoluluHenk]

Unfortunately, no.
And it seems like I won't find time anytime soon :(
sigh

[Maicon96]

I have the same use case -> so +1 for the "user demand"

[thangthan]

For all those arriving here via google:

A workaround is to create some other bean and @Inject your bean there... just so Quarkus knows it needs to register your bean for CDI injection.

@ApplicationScoped
public class JPAEntityListenerInjectionWorkaround {
  @Inject FooBean fooBean;
}

Then retrieve your bean instance in the EntityListener like this:
FooBean fooBean = CDI.current().select(FooBean.class).get();

Thank you so much, you saved me 24 hours searching for injecting Microprofile JsonWebToken to EntityListeners

[mkouba]

I'm not quite sure what the original problem is but if the FooBean is simply removed because it's considered unused a simpler solution is to annotate the FooBean class with @io.quarkus.arc.Unremovable (such beans are never removed even if not injected anywhere in the app).

[eliaharm]

public class JpaEntityListeners {

    @PrePersist
    public void prePersist(Object entity) {
        ReflectUtil.invoke(entity, "setCreateTime", LocalDateTime.now());
        ReflectUtil.invoke(entity, "setUpdateTime", LocalDateTime.now());
        JsonWebToken context = CDI.current().select(JsonWebToken.class).get();
        if (Objects.nonNull(context)) {
            String username = context.getClaim(Claims.preferred_username.name());
            if (Objects.nonNull(username)) {
                ReflectUtil.invoke(entity, "setCreateBy", username);
                ReflectUtil.invoke(entity, "setUpdateBy", username);
            }
        }
    }

    @PreUpdate
    public void preUpdate(Object entity) {
        ReflectUtil.invoke(entity, "setUpdateTime", LocalDateTime.now());
        JsonWebToken context = CDI.current().select(JsonWebToken.class).get();
        if (Objects.nonNull(context)) {
            String username = context.getClaim(Claims.preferred_username.name());
            if (Objects.nonNull(username)) {
                ReflectUtil.invoke(entity, "setUpdateBy", username);
            }
        }
    }
}

I use JsonWebToken context = CDI.current().select(JsonWebToken.class).get();

Dear @SoftMeng
That didn't work for me when persisting an object with REST resources for Hibernate ORM with Panache
it is returning null

[j-be]

@eliaharm I think you still need to @Inject JsonWebToken somewhere (it doesn't really matter where or if it is used there, as long as the bean injecting it is used, or marked as @io.quarkus.arc.Unremovable).

I think Quarkus is like "you don't use the bean? I'll not pack it then" on buildtime, and CDI.current() lookup alone do not classify as "use".

[ghost]

+1

[TheParad0X]

I am facing the same issue. What is currently the easiest way to inject a bean into my Entitylistener (that will also work in native mode) ? As most users here, I want to automatically update the created_by / updated_by column of my entities.

[j-be]

@TheParad0X CDI.current().select(FooBean.class).get(); still works fine for me in Quarkus 2.1. Just make sure the bean is injected somewhere else, or that it carries @io.quarkus.arc.Unremovable.

[yrodiere]

Fixed by #20708

[Felk]

Is this actually fixed? I am using Quarkus 2.7.1 and wrote an entity listener with @ApplicationScoped that @Injects an EntityManager. The injected instance stays null, but doing CDI.current().select(EntityManager.class).get(); works.

[yrodiere]

CDI injection in entity listeners does work, at least in the general case: https://github.com/quarkusio/quarkus/pull/20708/files#diff-7ed082417d8730c92d0dcf5c59e547878a5c298311afbd529f1a5c9591f150ccR73

I suppose injecting an entity manager into a component that is itself used by the entity manager could lead to cyclic dependency problems. If you do have problems, please open an issue with a reproducer, and we'll have a look.

[Felk]

@yrodiere Thanks, I was able to narrow the problem down a bit and opened #24340, though it is trivially worked around (don't have your listener methods be private).