@EnableAsync annotation in Spring Boot - Mini Project: Build & Apply

Using @EnableAsync Annotation in Spring Boot

📖 Scenario: You are building a Spring Boot application that needs to perform some tasks asynchronously to improve performance and user experience. For example, sending emails or processing files without blocking the main thread.

🎯 Goal: Learn how to enable asynchronous method execution in Spring Boot using the @EnableAsync annotation and create a simple asynchronous method.

📋 What You'll Learn

Create a Spring Boot application class

Enable asynchronous processing with @EnableAsync

Create a service class with an asynchronous method using @Async

Call the asynchronous method from the main application

💡 Why This Matters

🌍 Real World

Many web applications need to perform tasks like sending emails, processing files, or calling external APIs without blocking the main thread. Using @EnableAsync allows these tasks to run in the background improving responsiveness.

💼 Career

Understanding asynchronous processing with @EnableAsync is important for backend developers working with Spring Boot to build scalable and efficient applications.

1

Create the Spring Boot application class

Create a class called AsyncApplication annotated with @SpringBootApplication and add the main method that runs SpringApplication.run(AsyncApplication.class, args).

Spring Boot

@SpringBootApplication
public class AsyncApplication {
    public static void main(String[] args) {
        // Your code here
    }
}

Need a hint?

Use @SpringBootApplication on the class and inside main call SpringApplication.run with the class name and args.

2

Enable asynchronous processing with @EnableAsync

Add the @EnableAsync annotation to the AsyncApplication class above the @SpringBootApplication annotation to enable asynchronous method execution.

Spring Boot

// Add @EnableAsync annotation above @SpringBootApplication
@SpringBootApplication
public class AsyncApplication {
    public static void main(String[] args) {
        SpringApplication.run(AsyncApplication.class, args);
    }
}

Need a hint?

Place @EnableAsync directly above @SpringBootApplication on the class.

3

Create a service with an asynchronous method

Create a class called EmailService annotated with @Service. Inside it, create a method called sendEmail that takes a String recipient parameter and annotate this method with @Async. The method body can be empty or have a comment.

Spring Boot

// Create EmailService class with @Service annotation
// Add @Async annotation to sendEmail method
@Service
public class EmailService {
    public void sendEmail(String recipient) {
        // Your code here
    }
}

Need a hint?

Use @Service on the class and @Async on the method sendEmail.

4

Call the asynchronous method from the application

In the AsyncApplication class, add a @Bean method that returns a CommandLineRunner. Inside the runner, inject EmailService and call sendEmail("[e-mail]") to test asynchronous execution.

Spring Boot

// Add a @Bean method returning CommandLineRunner
// Inject EmailService and call sendEmail("[e-mail]") inside run method
@Bean
public CommandLineRunner runner(EmailService emailService) {
    return args -> {
        // Your code here
    };
}

Need a hint?

Create a @Bean method that returns a CommandLineRunner. Inside its run method, call sendEmail on the injected EmailService.