Spring Boot Async Tasks

Spring Boot provides an easy way to run asynchronous tasks using the @Async annotation. This is useful for executing tasks in the background, improving performance, and avoiding blocking the main thread.

🌟 Why Use @Async in Spring Boot?

Non-Blocking Execution: Runs tasks asynchronously without blocking the main thread.
Improved Performance: Executes independent tasks in parallel.
Better Scalability: Frees up resources for other processes.
Seamless Integration: Works with Spring Boot’s dependency injection and lifecycle management.

🌟 Prerequisites

Ensure you have the following:

☕ Java Development Kit (JDK) 17+
📦 Maven or Gradle installed
🔤 A Java IDE (e.g., IntelliJ IDEA, Eclipse)

🛠️ Step 1: Add Dependencies

To enable async processing, include spring-boot-starter-web in your pom.xml or build.gradle file.

Maven:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

Gradle:

implementation 'org.springframework.boot:spring-boot-starter-web'

📋 Step 2: Enable Async in Your Application

Annotate your main application class with @EnableAsync to enable asynchronous execution.

package com.example.async;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;

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

package com.example.async

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.scheduling.annotation.EnableAsync

@SpringBootApplication
@EnableAsync
class AsyncApplication

fun main(args: Array<String>) {
    runApplication<AsyncApplication>(*args)
}

📖 Step 3: Create an Async Task

Define an asynchronous method using @Async.

package com.example.async;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import java.time.LocalTime;

@Service
public class AsyncTask {

    @Async
    public void runTask() {
        System.out.println("Async task executed at: " + LocalTime.now());
    }
}

package com.example.async

import org.springframework.scheduling.annotation.Async
import org.springframework.stereotype.Service
import java.time.LocalTime

@Service
class AsyncTask {

    @Async
    fun runTask() {
        println("Async task executed at: ${LocalTime.now()}")
    }
}

🔄 Step 4: Create a Controller to Trigger Async Tasks

Create a REST controller to trigger the asynchronous task.

package com.example.async;

import org.springframework.web.bind.annotation.*;
import lombok.RequiredArgsConstructor;

@RestController
@RequestMapping("/async")
@RequiredArgsConstructor
public class AsyncController {

    private final AsyncTask asyncTask;

    @GetMapping("/run")
    public String triggerAsyncTask() {
        asyncTask.runTask();
        return "Async task triggered!";
    }
}

package com.example.async

import org.springframework.web.bind.annotation.*

@RestController
@RequestMapping("/async")
class AsyncController(
    private val asyncTask: AsyncTask
) {

    @GetMapping("/run")
    fun triggerAsyncTask(): String {
        asyncTask.runTask()
        return "Async task triggered!"
    }
}

▶️ Running the Application

Run the Spring Boot application:

./mvnw spring-boot:run

Or using Gradle:

gradle bootRun

🧪 Testing the Async Task

Trigger Async Task:

curl -X GET http://localhost:8080/async/run

Expected Console Output:

Async task executed at: 12:00:01

Spring Boot’s @Async annotation makes it easy to execute background tasks asynchronously. Whether you need to run long-running jobs, improve response times, or optimize resource usage, Spring’s async support provides a flexible and powerful solution.