@EnableAsync annotation in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @EnableAsync annotation in Spring Boot?

The @EnableAsync annotation tells Spring Boot to enable support for running methods asynchronously, meaning those methods can run in the background without blocking the main thread.

beginner

How do you mark a method to run asynchronously after enabling @EnableAsync?

You add the @Async annotation to the method you want to run asynchronously. This tells Spring to run that method in a separate thread.

intermediate

Where should you place the @EnableAsync annotation in a Spring Boot application?

You usually place <code>@EnableAsync</code> on a configuration class or the main application class to enable asynchronous processing across the app.

advanced

What happens if you call an <code>@Async</code> method from within the same class without going through Spring's proxy?

The @Async method will not run asynchronously because Spring uses proxies to manage async calls. Calling it internally bypasses the proxy, so it runs synchronously.

intermediate

Can you customize the thread pool used by @EnableAsync? How?

Yes, you can customize the thread pool by defining a TaskExecutor bean and specifying it in the @Async annotation or by overriding the default executor in the configuration.

What does the @EnableAsync annotation do in a Spring Boot app?

A Enables asynchronous method execution

B Disables asynchronous processing

C Enables synchronous method execution

D Configures database connections

@EnableAsync activates support for running methods asynchronously in Spring Boot.

Which annotation marks a method to run asynchronously after enabling @EnableAsync?

A @Async

B @AsyncMethod

C @EnableAsyncMethod

D @RunAsync

The @Async annotation marks methods to run asynchronously.

Where is the best place to put the @EnableAsync annotation?

A On every asynchronous method

B On the controller methods only

C On the database entity classes

D On a configuration or main application class

@EnableAsync is placed on a configuration or main class to enable async support app-wide.

What happens if you call an @Async method from the same class internally?

A It causes a compile error

B It runs asynchronously as expected

C It runs synchronously, not asynchronously

D It throws a runtime exception

Internal calls bypass Spring proxies, so @Async methods run synchronously.

How can you customize the thread pool used by @EnableAsync?

A By setting a property in <code>application.properties</code> only

B By defining a custom <code>TaskExecutor</code> bean

C By adding <code>@ThreadPool</code> annotation

D You cannot customize the thread pool

You customize the thread pool by defining a TaskExecutor bean in your configuration.

Explain how @EnableAsync and @Async work together in Spring Boot to run methods asynchronously.

Think about how Spring knows which methods to run in the background.

Describe a common pitfall when calling an @Async method from within the same class and how to avoid it.

Consider how Spring manages async calls behind the scenes.