Spring Framework FAQ: Top Questions

Spring has a built-in event publishing mechanism that follows the Observer pattern. Beans can publish and listen to custom or predefined events.

🗺️ Components:

• ApplicationEventPublisher to publish events.
• @EventListener or ApplicationListener to listen for them.

📥 Example:

public class MyEvent extends ApplicationEvent {
  public MyEvent(Object source) {
    super(source);
  }
}

@Component
public class MyListener {
  @EventListener
  public void handleEvent(MyEvent event) {
    System.out.println("Handled event: " + event);
  }
}

🏆 Expected Output:

Custom event is published and handled by listener bean.

🛠️ Use Cases:

• Decoupling components via event communication.
• Triggering background or audit logic upon domain events.