Inject ApplicationScoped inside ApplicationScoped throws NullPointerException

Describe the bug

Basically: I want the Controller class to have a generic IUseCase (constructor injected) and the UseCase to have a generic IService (constructor injection).

Controller -> UseCase -> Server Controller -> UseCase -> MockServer Controller -> UseCaseMock

public class Controller {
    private final IUseCase useCase;

    @Inject
    public Controller(IUseCase getUseCase) {
        this.useCase = getUseCase;
    }

@ApplicationScoped
public class UseCase implements IUseCase {

    private IService service;

    @Inject
    public UseCase(IService webService) {
        this.service = webService;
        service.init();
    }
}

public class UseCaseMock implements IUseCase {
...
}

@ApplicationScoped
public class Service implements IService {
...
}

public class ServiceMock implements IService {
...
}

Expected behavior

When running the application, because of the @ApplicationScoped annotation, I expect that: Controller has the UseCase constructor injected and that the UseCase has Service constructor injected.

Actual behavior

Method threw ‘java.lang.NullPointerException’ exception. Cannot evaluate …usecases.impl.UseCase_ClientProxy.toString()

it didnt inject it, even tho it was annotated with ApplicationScoped.

How to Reproduce?

In a nutshell: have a class which constructor injects an ApplicationScoped class which constructor injects an ApplicationScoped class.

public class Controller {
    private final IUseCase useCase;

    @Inject
    public Controller(IUseCase getUseCase) {
        this.useCase = getUseCase;
    }

@ApplicationScoped
public class UseCase implements IUseCase {

    private IService service;

    @Inject
    public UseCase(IService webService) {
        this.service = webService;
        service.init();
    }
}

public class UseCaseMock implements IUseCase {
...
}

@ApplicationScoped
public class Service implements IService {
...
}

public class ServiceMock implements IService {
...
}

Output of uname -a or ver

No response

Output of java -version

openjdk version “1.8.0_312”

GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.4.2.Final

Build tool (ie. output of mvnw --version or gradlew --version)

Apache Maven 3.8.5

Additional information

No response

[geoand]

I see that Controller is not annotated with a CDI annotation. How are you creating / using it?

[mkouba]

I’m going to close this issue. @vinland-saga Feel free to reopen if you find a way to reproduce the NPE.