Injecting a Kotlin EJB into a Java POJO

Question

Just started experimenting with Kotlin (1.2.60) & Java (EE8). All is deployed successfully in an EAR file onto JBoss WildFly 13.0.0.Final using Java EE 8, EJB 3.2. No exceptions are shown in the log.

I've created a Kotlin EJB:

@Stateless
@LocalBean
open class NOTiFYEJB {

    open val logger = LoggerFactory.getLogger("NOTiFYEJB")

    open fun sayHelloKotlinWorld() = {
        logger.info(">>>>> sayHelloKotlinWorld .....")
    }
}

Which is 'registered' on WildFly 13:

08:06:26,131 INFO [org.jboss.as.ejb3.deployment] (MSC service thread 1-1) WFLYEJB0473: JNDI bindings for session bean named 'NOTiFYEJB' in deployment unit 'subdeployment "NOTiFYwellJAR.jar" of deployment "NOTiFYwell.ear"' are as follows:

java:global/NOTiFYwell/NOTiFYwellJAR/NOTiFYEJB!com.notifywell.kotlin.ejb.NOTiFYEJB java:app/NOTiFYwellJAR/NOTiFYEJB!com.notifywell.kotlin.ejb.NOTiFYEJB java:module/NOTiFYEJB!com.notifywell.kotlin.ejb.NOTiFYEJB ejb:NOTiFYwell/NOTiFYwellJAR/NOTiFYEJB!com.notifywell.kotlin.ejb.NOTiFYEJB java:global/NOTiFYwell/NOTiFYwellJAR/NOTiFYEJB java:app/NOTiFYwellJAR/NOTiFYEJB java:module/NOTiFYEJB

I inject this into a @model Java Pojo and call the method:

@Model
@Path("/")
public class NOTiFYwellModel {

    @Inject
    private NOTiFYEJB nOTiFYEJB;

    public NOTiFYwellModel() {
    }

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    @Path("/say-hello-kotlin-world")
    public Response sayHelloKotlinWorld() {
        logger.info(">>>> sayHelloKotlinWorld nOTiFYEJB = {}", nOTiFYEJB);

        nOTiFYEJB.sayHelloKotlinWorld();

        return null; // Just for test
    }
}

When I run the Unit test:

String url = "http://localhost:8080/NOTiFYwell/notifywell/say-hello-kotlin-world";

HttpGet httpGet = new HttpGet(url);
httpGet.setHeader(CONTENT_TYPE, APPLICATION_JSON);

// Execute and get the response.
HttpClient httpClient = HttpClientBuilder.create().build();
HttpResponse response = httpClient.execute(httpGet);

The method in the @Model NOTiFYwellModel class is called:

08:07:00,459 INFO [com.notifywell.model.NOTiFYwellModel] (default task-1) >>>> sayHelloKotlinWorld nOTiFYEJB = Proxy for view class: com.notifywell.kotlin.ejb.NOTiFYEJB of EJB: NOTiFYEJB

But the next line which calls the method in the (Injected) Kotlin EJB is not executed.

nOTiFYEJB.sayHelloKotlinWorld();

It is as though the 'local' interface is not found.

This 'architecture/design' is working fine everywhere else when I inject a (local) Java EJB.

Are you able to use Weld CDI to @Inject a Kotlin EJB into a Java Class?

@duffymo: ejb 3.2 and the lightweight pure web versions is very much 201x (even with x approaching 9) All standardized and not requirering spring so no need for all the spring-* wrappers — Kukeltje, Aug 06 '18 at 20:57
I like the simplicity of EJB 3.2 with CDI on EE8 and the speed of JBoss WildFly 13. I do find that rather ironic (criticising 2010/2020s EJBs) when Spring had to launch Spring Boot as too many people were finding Spring far too complicated. A Framework for a Framework. I know it now (finally) has annotations but it was XML configuration hell for many years! — NOTiFY, Aug 07 '18 at 06:33
What do you mean the method is ignored? Not called at all or blowing up? Have you debugged it? From EE PoV this normally works. Also, if you are running a true unit test, your EJB probably won't work because there is no EJB container active. — Siliarus, Aug 07 '18 at 08:06
The "unit" test is a Web Service call. See the annotations: @GET @Produces(MediaType.APPLICATION_JSON) @Path("/say-hello-kotlin-world"). It is ignored / not called as the 'logger' in the Kotlin EJB is not printing the message ">>>>> sayHelloKotlinWorld .....". Nothing "blows-up". — NOTiFY, Aug 07 '18 at 08:15

NOTiFY · Answer 1 · 2018-08-08T06:42:26.563

Unlike EJB 3.2 with Java EE 8, I needed to create and implement an Interface on my Kotlin EJB, rather than just annotating the EJB.

I also needed to 'override' & specify ': Unit' for my void method:

Kotlin EJB:

@Stateless
@LocalBean
open class NOTiFYKotlinEJB : NOTiFYKotlinEJBInterface {

    /**
     *
     */
    override fun sayHelloKotlinWorld(): Unit {
        println("***** sayHelloKotlinWorld .....")
    }
}

Interface:

interface NOTiFYKotlinEJBInterface {

    fun sayHelloKotlinWorld() : Unit {}

}

My @Model POJO calls the Kotlin EJB method and outputs:

22:31:31,175 INFO [com.notifywell.model.NOTiFYwellModel] (default task-1) >>>> sayHelloKotlinWorld nOTiFYEJB = Proxy for view class: com.notifywell.kotlin.ejb.NOTiFYKotlinEJB of EJB: NOTiFYKotlinEJB 22:31:31,191 INFO [stdout] (default task-1) ***** sayHelloKotlinWorld .....

Injecting a Kotlin EJB into a Java POJO

1 Answers1