Spring Boot 4 Microservices & REST APIs · Lesson

Scheduling with @Scheduled

Run tasks on a fixed rate or cron.

Scheduling with @Scheduled is a free Spring Boot 4 Microservices & REST APIs lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Spring Boot 4 Microservices & REST APIs learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Scheduling in Spring Boot

Spring Boot lets you run methods automatically on a schedule without any external cron daemon. You annotate a method with @Scheduled and Spring invokes it repeatedly in the background.

Perfect for cleanup jobs, polling, report generation
No extra infrastructure needed

Enabling scheduling

Scheduling is off by default. You turn it on with @EnableScheduling on a configuration class (often the main application class).

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

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

fixedRate

fixedRate runs the method at a fixed interval measured from the start of one run to the start of the next. The value is in milliseconds.

@Component
public class RateTask {

    @Scheduled(fixedRate = 5000)
    public void report() {
        System.out.println("Runs every 5 seconds");
    }
}

fixedDelay

fixedDelay waits a fixed gap after the previous run finishes before starting the next one. Use it when runs must never overlap.

@Scheduled(fixedDelay = 5000)
public void process() {
    // next run starts 5s AFTER this one ends
    doWork();
}

fixedRate vs fixedDelay

The key difference is the reference point:

fixedRate = interval between start times (can overlap if a run is slow)
fixedDelay = gap between end and next start (never overlaps)

initialDelay

initialDelay delays the first execution after startup. Combine it with fixedRate or fixedDelay to avoid running immediately on boot.

@Scheduled(initialDelay = 10000, fixedRate = 5000)
public void warmThenRun() {
    // waits 10s after startup, then every 5s
}

cron expressions

For calendar-based scheduling use cron. Spring cron has 6 fields: second, minute, hour, day-of-month, month, day-of-week.

@Scheduled(cron = "0 0 9 * * MON-FRI")
public void weekdayMorning() {
    // 09:00:00 every weekday
}

Reading cron fields

An asterisk * means "every value". A ? can be used in day-of-month or day-of-week when one is unspecified. Ranges (MON-FRI), lists (1,15) and steps (*/10) are supported.

@Scheduled(cron = "*/30 * * * * *") // every 30 seconds
public void everyHalfMinute() { }

@Scheduled(cron = "0 0 0 1 * *") // midnight on the 1st of every month
public void monthly() { }

Time zones

By default cron uses the server time zone. Set zone to make schedules explicit and predictable across environments.

@Scheduled(cron = "0 0 8 * * *", zone = "Europe/Istanbul")
public void eightAmIstanbul() { }

Externalizing the schedule

Hardcoding intervals is inflexible. Use a property placeholder so the schedule can change per environment without recompiling.

@Scheduled(fixedRateString = "${app.report.rate:5000}")
public void report() { }

// application.yml
// app:
//   report:
//     rate: 10000

Scheduling pitfalls

By default a single thread runs all scheduled tasks, so a slow task can delay others. For parallel execution configure a ThreadPoolTaskScheduler. Also keep scheduled methods idempotent in case of restarts.

Quick Check

Test your understanding of scheduling.

Recap

You learned how to schedule work in Spring Boot:

@EnableScheduling turns the feature on
fixedRate = start-to-start, fixedDelay = end-to-start
cron handles calendar schedules; set zone for clarity
Externalize intervals with property placeholders

Frequently asked questions

Is the “Scheduling with @Scheduled” lesson free?

Yes — the full text of “Scheduling with @Scheduled” is free to read here on the web, and the Spring Boot 4 Microservices & REST APIs course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Spring Boot 4 Microservices & REST APIs course, upgrade to CoddyKit PRO.

What will I learn in “Scheduling with @Scheduled”?

Run tasks on a fixed rate or cron. You practise Spring Boot 4 Microservices & REST APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Spring Boot 4 Microservices & REST APIs?

No prior experience is required. Spring Boot 4 Microservices & REST APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Scheduling with @Scheduled” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Spring Boot 4 Microservices & REST APIs lesson?

Yes. Every Spring Boot 4 Microservices & REST APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

← Back to Spring Boot 4 Microservices & REST APIs