How to solve org.apache.camel.FailedToCreateProducerException CaughtExceptionMessage: Failed to create Producer for endpoint?

Question

I upgraded Camel components and code from 2.X.X to 3.7.3

Also, I recompiled sources in Java 11 before they worked in Java 8.

Example of the route:

from(direct:xyz)
  .to(URL_A)
  .transform()
  ...

The issue arrives because after to, I get null.

I moved from camel-http4 to camel-http, checked properties of the libs but still cannot get what is wrong?

The error I am getting:

CaughtExceptionType: org.apache.camel.FailedToCreateProducerException  CaughtExceptionMessage: Failed to create Producer for endpoint: direct:xyz1616073923650. Reason: java.lang.NullPointerException  StackTrace: org.apache.camel.FailedToCreateProducerException: Failed to create Producer for endpoint: direct:xyz1616073923650. Reason: java.lang.NullPointerException
    at org.apache.camel.support.cache.DefaultProducerCache.acquireProducer(DefaultProducerCache.java:154)
    at org.apache.camel.processor.RecipientListProcessor.createProcessorExchangePairs(RecipientListProcessor.java:219)
    at org.apache.camel.processor.MulticastProcessor.process(MulticastProcessor.java:276)
    at org.apache.camel.processor.RecipientList.sendToRecipientList(RecipientList.java:222)
    at org.apache.camel.processor.RecipientList.process(RecipientList.java:185)
    at org.apache.camel.processor.Pipeline$PipelineTask.run(Pipeline.java:90)
    at org.apache.camel.impl.engine.DefaultReactiveExecutor$Worker.schedule(DefaultReactiveExecutor.java:148)
    at org.apache.camel.impl.engine.DefaultReactiveExecutor.scheduleMain(DefaultReactiveExecutor.java:60)
    at org.apache.camel.processor.Pipeline.process(Pipeline.java:147)
    at org.apache.camel.impl.engine.CamelInternalProcessor.process(CamelInternalProcessor.java:312)
    at org.apache.camel.component.direct.DirectProducer.process(DirectProducer.java:84)
    at org.apache.camel.impl.engine.SharedCamelInternalProcessor.process(SharedCamelInternalProcessor.java:218)
    at org.apache.camel.impl.engine.SharedCamelInternalProcessor$1.process(SharedCamelInternalProcessor.java:112)
    at org.apache.camel.impl.engine.DefaultAsyncProcessorAwaitManager.process(DefaultAsyncProcessorAwaitManager.java:83)
    at org.apache.camel.impl.engine.SharedCamelInternalProcessor.process(SharedCamelInternalProcessor.java:109)
    at org.apache.camel.support.cache.DefaultProducerCache.send(DefaultProducerCache.java:189)
    at org.apache.camel.impl.engine.DefaultProducerTemplate.send(DefaultProducerTemplate.java:176)
    at org.apache.camel.impl.engine.DefaultProducerTemplate.send(DefaultProducerTemplate.java:172)
    at org.apache.camel.impl.engine.DefaultProducerTemplate.send(DefaultProducerTemplate.java:153)
    at org.apache.camel.impl.engine.DefaultProducerTemplate.sendBody(DefaultProducerTemplate.java:187)
    at org.apache.camel.impl.engine.DefaultProducerTemplate.sendBody(DefaultProducerTemplate.java:457)

Comment: I cannot even find a further way out of here, so any suggestions are welcome.

UPDATE:

After debugging further, I understood that the bug was further in the route.

from(direct:xyz)
  .to(URL_A)
  .transform()
  ...
  .recipientList(exchangeProperty("event"))

UPDATE 2:

I posted a question/bug into the Camel Jira board.

UPDATE 3:

I add an example of my test classes, the route under test looks like the one above.

Spring Boot app that starts route, context:

@SpringBootApplication
@PropertySource("classpath:application-test.properties")
class TestApp {

    public static void main(String[] args) {
        SpringApplication.run(TestApp.class, args);
    }
}

Test itself:

@RunWith(SpringRunner.class)
@TestPropertySource(locations = "application-test.properties")
@SpringBootTest(classes = TestApp.class, webEnvironment = DEFINED_PORT)
public class FunctionalTest {

    @Autowired
    private EventConsumeCreator eventConsumerCreator;

    private List<Endpoint> consumers;

    private static final MockComponent MOCK_COMPONENT = new MockComponent();
    
    @Before
    public void before() {
        // Setting Wiremock and LogAsserts

        consumers = eventConsumerCreator.getConsumers();
      
        consumers.clear();
        consumers.add(new MockEndpoint("direct:xyz", MOCK_COMPONENT));

    }

    @Test
    public checkNumEvents() {
      // Make requests to endpoints
      // Verify logs
      // Check wiremock asserts

      assertThat(numEvents(consumers), is(1));
    }

}

Utility class for creating consumers:

@Component
public class EventConsumerCreator {

    private List<Endpoint> consumers = new LinkedList<>();

    private CamelContext camelContext;

    @Autowired
    public EventConsumerCreator(CamelContext camelContext) {
        this.camelContext = camelContext;
    }

    public List<Endpoint> getConsumers() {
        return consumers;
    }

    public Endpoint createConsumer(String identifier) {
        Endpoint endpoint = createEndpoint(identifier);
        consumers.add(endpoint);
        return endpoint;
    }

    private Endpoint createEndpoint(String identifier) {
        DirectComponent component = camelContext.getComponent("direct", DirectComponent.class);
        try {
            return component.createEndpoint("direct://" + identifier);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

Answer 1

Thanks to @Claus Ibsen's response in Jira, I solved this issue.

The solution was to:

1. Add @Autowired private CamelContext camelContext in FunctionalTest
2. In @Before iterate over all endpoints and do

camelContext.addEndpoint(endpoint.getEndpointUri(), endpoint);
endpoint.start();

3. In the @After statement, stop running endpoints

endpoint.stop();
camelContext.removeEndpoint(endpoint);

Comment: If you get in a situation like this, think if you can rely on Spring/Camel auto-configurations. If not, try to recreate Camel-ish steps manually.