Can not inject EntityManager

[hantsy]

I am preparing a new template project for Jakarta EE 10, https://github.com/hantsy/jakartaee10-starter-boilerplate

• Java 17
• Jakarta EE 10
• OpenLiberty 23.0.0.5

I tried to add tests for CDI repository and EJB stateless bean. https://github.com/hantsy/jakartaee10-starter-boilerplate/blob/master/src/test/java/com/example/it/CdiTodoRepositoryTest.java

@ExtendWith(ArquillianExtension.class)
public class CdiTodoRepositoryTest {
    private final static Logger LOGGER = Logger.getLogger(CdiTodoRepositoryTest.class.getName());

    @Deployment
    public static WebArchive createDeployment() {
        return ShrinkWrap.create(WebArchive.class, "test.war")
                .addPackage(Todo.class.getPackage())
                .addClasses(CdiTodoRepository.class, CrudRepository.class)
                .addClass(DbUtil.class)
                .addAsResource("test-persistence.xml", "META-INF/persistence.xml")
                .addAsWebInfResource(EmptyAsset.INSTANCE, "beans.xml");
    }

    @Inject
    CdiTodoRepository todos;

    @PersistenceContext
    EntityManager entityManager;

    @Resource(lookup = "java:comp/DefaultDataSource")
    DataSource dataSource;

    @Inject
    UserTransaction utx;

    private DbUtil dbUtil;

    @BeforeEach()
    public void setup() throws Exception {
        utx.begin();
        dbUtil = new DbUtil(dataSource);
        dbUtil.clearTables();
        utx.commit();
    }

    @Test
    public void testNewTodo() throws Exception {
        utx.begin();
        LOGGER.log(Level.INFO, "new todo ... ");
        Todo todo = Todo.of("test");
        var saved = todos.save(todo);
        utx.commit();

        dbUtil.assertCount("todos", 1);
        var getById = entityManager.find(Todo.class, saved.getId());
        assertNotNull(getById);
        assertEquals("test", saved.getTitle());
    }
    
}

The above entityManger.find throws a NPE. https://github.com/hantsy/jakartaee10-starter-boilerplate/actions/runs/5235222832/jobs/9451902412

Only OpenLiberty encountered this issue, check my Github actions run result.

[hantsy]

But I checked my Jakarta EE 8 version, https://github.com/hantsy/jakartaee8-starter-boilerplate similar codes worked well.

https://github.com/hantsy/jakartaee8-starter-boilerplate/blob/master/src/test/java/com/example/it/OrderDaoTest.java

[hantsy]

There are several posts on Stackoverflow reported this issue, https://stackoverflow.com/questions/66971101/entitymanager-is-null-in-my-test-class-but-working-in-my-service
https://stackoverflow.com/questions/41553376/arquillian-on-was-remote-container-and-persistencecontext

[Azquelt]

Sounds entityManager is not injected. Arquillian does its own injection of resources, so that could be going wrong I guess.

I would want someone who knows JPA to check the setup is correct.

I think the relevant parts of the configuration are (in addition to the test class above):
server.xml
persistence.xml

[Azquelt]

Looked some more and noted that todos.save(todo); does not throw an NPE, showing that the injection of EntityManager into CdiTodoRepository did work correctly, so the JPA config is probably fine and the problem is just with arquillian injecting the EntityManager into the test class.

[Azquelt]

As a workaround you could try calling CdiTodoRepository.findById instead of entityManager.find in your test.

[Azquelt]

This code from Arquillian should run to do injection for the test class:

    protected void injectNonContextualInstance(BeanManager manager, Object instance) {
        CreationalContext<Object> creationalContext = getCreationalContext();
        InjectionTarget<Object> injectionTarget = (InjectionTarget<Object>) manager
                .getInjectionTargetFactory(manager.createAnnotatedType(instance.getClass()))
                .createInjectionTarget(null);
        injectionTarget.inject(instance, creationalContext);
    }

Where manager is the bean manager looked up from OSGi and instance is the test class instance (i.e. CdiTodoRepositoryTest)

I would want to look to see why that isn't working when the regular injection of CdiTodoRepository appears to be fine.

Edit: updated to link to the up to date version from the arquillian repository.

[hantsy]

The EJB version EjbTodoRepositoryTest also failed. https://github.com/hantsy/jakartaee10-starter-boilerplate/blob/master/src/test/java/com/example/it/EjbTodoRepositoryTest.java

And Only OpenLiberty failed, but the Jakarta EE 8 version worked well, https://github.com/hantsy/jakartaee8-starter-boilerplate/blob/master/src/test/java/com/example/it/OrderDaoTest.java (check the project build status), I am not sure where is wrong in the liberty arquillian when upgrading to Jakarta namespace.

And for this same tests, both GlassFish and WildFly worked well.

Checked the build status of this project. https://github.com/hantsy/jakartaee10-starter-boilerplate

[Azquelt]

The EJB version is doing the same thing, using @PersistenceContext to inject an EntityManager into the test class.

Even though it's an EJB test, it would still be the CDIInjectionEnricher which handles that field in the test class.

[Azquelt]

I am not sure where is wrong in the liberty arquillian when upgrading to Jakarta namespace.

Yeah, it is odd. I'm not sure either.

There is a separate version of CDIInjectionEnricher for jakarta classes but the code is the same and it must be working somewhat otherwise the @Inject CdiTodoRepository would also be broken.

[hantsy]

From the stackoverflow issues, it seems the issue was occurred when liberty arquillian is upgraded to EE9/Jakarta. It should be existed for years.

I also prepared a Jakarta EE 9 template project, but it did not contains a JPA test.

In the new Jakarta EE 10 template project, I try to add more missing examples to demo more specs in the Jakarta EE 8 version, and encountered this issue.

[hantsy]

Or there are some specific config in the server.xml for Jakarta EE9/10?

[Azquelt]

As a workaround you could try calling CdiTodoRepository.findById instead of entityManager.find in your test.

Could you confirm whether this works? It would help to confirm my theory as to where the problem is.

If it does work, then I'd be looking for a bug in the way CDI injects EE resources like EntityManager which only occurs when injecting a non-contextual instance and was introduced since EE9.

[hantsy]

The CdiTodoRepository.save is working well, so injecting CdiTodoRepository is 100% Ok.

Ok, I have updated the tests, add the tests as you expected.

Check the new updated https://github.com/hantsy/jakartaee10-starter-boilerplate/blob/master/src/test/java/com/example/it/CdiTodoRepositoryTest.java

and build result:
https://github.com/hantsy/jakartaee10-starter-boilerplate/actions/runs/5244915122/jobs/9471592175

[hantsy]

@Azquelt Any update of this issue?

[Azquelt]

Sorry, I thought I'd replied here.

I had a look into it and it seems like liberty is scanning for classes which should have EE resources injected (with @Resource, @PersistenceContext etc.)

The arquillian test class isn't one that we would generally inject into - it's not a CDI bean or an EE component - it looked like when the CDIInjectionEnricher runs, liberty looks for metadata for the injection point on the test class and doesn't find any because it wasn't scanned at startup.

I haven't been able to look at why you only see this problem with EE 9 onwards and not EE 10.

This issue is mostly impacting arquillian tests because the CDIInjectionEnricher is trying to do EE resource injection into things which aren't EE components.

I also couldn't find anything in the CDI or EE spec to suggest that this behaviour is allowed (though it is odd if it used to work but now doesn't).

Given that this is only impacting arquillian tests relying on behaviour which isn't required in the spec, I don't have enough time to continue looking at this at the moment.