Asynchronous Methods (@Async) — Spring Technical Interview Questions & Answers

Running a method on a separate thread.

Asynchronous Methods (@Async)

  • @Async runs a method on another thread so the caller is not blocked.
  • Enable with @EnableAsync.
  • Useful for sending email/notifications after a request returns.
  • Return types can be void or Future/CompletableFuture style results.
  • Forgetting to enable async, so the annotation does nothing.
  • Async = non-blocking call for background work.

Technical Interview Tip: Enable flag + use case (email after signup).

Code Examples for Asynchronous Methods (@Async)

Asynchronous Methods (@Async) — working example

// Topic: Asynchronous Methods (@Async)
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
class TopicController {
  @GetMapping("/api/topic")
  String topic() {
    return "Spring Boot: Asynchronous Methods (@Async)";
  }
}

Asynchronous Methods (@Async): GET /api/topic returns this title string.

How to Explain Asynchronous Methods (@Async) to an Interviewer

What is Asynchronous Methods (@Async) (sb misc)?

Used for a short Asynchronous Methods @Async sb misc example a small REST app Not just the heading

Give one small example of Asynchronous Methods (@Async) (sb misc).

the smallest Asynchronous Methods @Async sb misc example you can type Running a method on a separate thread

What mistake do beginners make with Asynchronous Methods (@Async) (sb misc)?

only saying “Asynchronous Methods @Async sb misc” with no example Show the fix

Where do you use Asynchronous Methods (@Async) (sb misc)?

a small REST app a short Asynchronous Methods @Async sb misc example