@Async not working for method having return type void

Question

I wanted to make a method writing to DB as async using @Async annotation.

I marked the class with the annotation @EnableAsync:

@EnableAsync
public class FacialRecognitionAsyncImpl {

    @Async
    public void populateDataInPushQueue(int mediaId, int studentId) {
        //myCode
    }
}

while calling the populateDataInPushQueue method, the write operation should be executed in another thread and the flow should continue from the class I am calling this method. But this is not happening and the program execution is waiting for this method to complete.

Answer 1

The @Async annotation has few limitations - check whether those are respected:

• it must be applied to public methods only
• it cannot be called from the same class as defined
• the return type must be either void or Future

The following can be found at the documentation of @EnableAsync:

Please note that proxy mode allows for the interception of calls through the proxy only; local calls within the same class cannot get intercepted that way.

Another fact is that the class annotated with @EnableAsync must be a @Configuration as well. Therefore start with an empty class:

@EnableAsync
@Configuration
public class AsyncConfiguration { }