Spring Boot Scheduled Tasks

Spring Boot allows developers to easily schedule and execute background tasks using the @Scheduled annotation. This is useful for running periodic jobs, automation tasks, and batch processing without manual intervention.

🌟 Why Use @Scheduled in Spring Boot?

• Automate Tasks: Run jobs periodically without human interaction.
• Efficient Resource Usage: Schedule tasks without blocking main threads.
• Supports Fixed Rate, Fixed Delay, and Cron Expressions.
• 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 scheduling, you need to 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'

Why spring-boot-starter-web? Spring Boot applications using @Scheduled need a running Spring Context. Including spring-boot-starter-web ensures that the application lifecycle is properly managed.

📋 Step 2: Enable Scheduling in Your Application

To enable scheduling, annotate your main application class with @EnableScheduling.

• Java
• Kotlin

package com.example.scheduled;

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

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

package com.example.scheduled

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

@SpringBootApplication
@EnableScheduling
class ScheduledApplication

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

📖 Step 3: Create a Scheduled Task

Define a scheduled task using @Scheduled.

• Java
• Kotlin

package com.example.scheduled;

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

@Service
public class ScheduledTask {

    @Scheduled(fixedRate = 5000)
    public void runTask() {
        System.out.println("Scheduled task executed at: " + LocalTime.now());
    }
}

package com.example.scheduled

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

@Service
class ScheduledTask {

    @Scheduled(fixedRate = 5000)
    fun runTask() {
        println("Scheduled task executed at: ${LocalTime.now()}")
    }
}

▶️ Running the Application

Run the Spring Boot application:

./mvnw spring-boot:run

Or using Gradle:

gradle bootRun

The scheduled task will execute every 5 seconds and print a timestamp.

🧪 Testing the Scheduled Task

Expected Console Output:

Scheduled task executed at: 12:00:01
Scheduled task executed at: 12:00:06
Scheduled task executed at: 12:00:11

Spring Boot’s @Scheduled annotation makes it easy to run background tasks on a schedule. Whether you need fixed-rate jobs, cron-based scheduling, or delayed execution, Spring provides a flexible and powerful scheduling solution.