@TransactionalEventListener doesn't works where as @EventListener works like charms for the same context

Question

I'm working in an event-driven design of spring boot application.

The code consists of following files:

1. Spring boot: ApplicationEvent File i.e MyBusinessEvent.{java

   @Data
   @AllArgsConstructor
   public class MyBusinessEvent {
   
      private String data;
   
   }
   

2. Event Publisher File: MyBusinessService.java

   @Slf4j
   @Service
   public class MyBusinessService {
   
       private final ApplicationEventPublisher applicationEventPublisher;
   
       @Autowired
       public MyBusinessService(
               ApplicationEventPublisher applicationEventPublisher) {
   
           this.applicationEventPublisher = applicationEventPublisher;
       }
   
       @Override
       public void save() {
           String data = "Testing event data";
           MyBusinessEvent event = new MyBusinessEvent(data);
           applicationEventPublisher.publishEvent(event);
       }
   }
   

3. EventListener : MyBusinessEventListener.java

   @Slf4j
   @Component
   public class MyBusinessEventListener {
   
       @EventListener
       public void handleEvent(MyBusinessEvent myBusinessEvent) {
           log.info("[MyBusinessEventListener] New event received with following data: {}", myBusinessEvent);
       }
   }
   

The point is when Listener file consists @EventListener then the app works as expected but when I do @TransactionEventListener. For example:

4. TransactionalEventListener : MyBusinessEventListener.java

   @Slf4j
   @Component
   public class MyBusinessEventListener {
   
       @TransactionalEventListener
       public void handleEvent(MyBusinessEvent myBusinessEvent) {
           log.info("[MyBusinessEventListener] New event received with following data: {}", myBusinessEvent);
       }
   }
   

with @TransactionalEventListener, it doesn't work at all.

The application doesn't through any exception (not even at runtime) but there is no logging as expected.

Is any configuration missing?

Answer 1

Add @Transactional annotation to MyBusinessService.save should fix this issue.

As per java documentation, @TransactionalEventListener work within @Transactional boundary.

Here what documentation says,

If the event is not published within the boundaries of a managed transaction, the
 * event is discarded unless the {@link #fallbackExecution} flag is explicitly set.

If you don't want your service method in transaction boundary then use @TransactionalEventListener(fallbackExecution = true)

EDIT: There are three possible solutions to the above problem.

i. Mark class as @Transactional to be considered as transactional

@Transactional
@Service
public class MyBusinessService {

    private final ApplicationEventPublisher applicationEventPublisher;

    @Autowired
    public MyBusinessService(
            ApplicationEventPublisher applicationEventPublisher) {

        this.applicationEventPublisher = applicationEventPublisher;
    }

    @Override
    public void save() {
        String data = "Testing event data";
        MyBusinessEvent event = new MyBusinessEvent(data);
        applicationEventPublisher.publishEvent(event);
    }
 }

ii. Make the specific method of service as @Transactional

@Override
@Transactional
public void save() {
    String data = "Testing event data";
    MyBusinessEvent event = new MyBusinessEvent(data);
    applicationEventPublisher.publishEvent(event);
}

iii. If you don't want your service method in transaction boundary then use

@Slf4j
@Component
public class MyBusinessEventListener {

    @TransactionalEventListener(fallbackExecution = true)
    public void handleEvent(MyBusinessEvent myBusinessEvent) {
        log.info("[MyBusinessEventListener] New event received with following data: {}", myBusinessEvent);
    }
}