When diving into the world of Java-based job scheduling, Quartz Scheduler stands out as a robust and flexible solution. But beyond basic tutorials, real understanding often comes from building something tangible. In this blog, I’ll walk you through my experience of learning Quartz Scheduler by building a real-time System Resource Monitoring application using Spring Boot.

What We Built

A lightweight Spring Boot application that:

• Monitors CPU and memory usage of a Windows machine
• Logs data into a CSV file
• Uses Quartz Scheduler to control monitoring intervals
• Exposes REST APIs to fetch logs, configure schedule, and view system metadata

This project was built with the intention of understanding Quartz in a practical, useful context.

Why Quartz Scheduler?

Quartz is a powerful and mature job scheduling library that supports:

• Cron-based scheduling
• Simple time-based intervals
• Persistent jobs
• Clustering and more

In our case, it was a perfect fit to schedule a recurring monitoring job that logs system resource usage every few seconds.

Tech Stack

• Java 17
• Spring Boot 3+
• Quartz Scheduler
• OSHI (Operating System & Hardware Info)
• Maven

Core Features

Each of these endpoints was backed by a clean service layer and a Quartz-triggered job that handled the actual resource capture and file writing.

Learning Points

Job Scheduling

I learned how to:

• Define a job using QuartzJobBean
• Register the job with a SchedulerFactoryBean
• Dynamically reschedule jobs

CSV File Logging

Instead of using a database, I wrote logs to a simple CSV file, which helped me focus more on the scheduling mechanics.

Real-time System Monitoring

Using the OSHI library, I captured:

• Current CPU load (between ticks)
• Used and total memory

REST APIs

I added a controller layer to make the application easily testable and extensible. Through simple GET and POST endpoints, users can:

• See logs
• Configure job frequency
• Access system metadata

Project Setup & Usage

GitHub Repo: QuartzSystemMonitor by akshay-0505

Prerequisites

• Java 17+
• Maven 3+

How to Run

# Clone the repository
https://github.com/akshay-0505/QuartzSystemMonitor.git
cd QuartzSystemMonitor

# Build the project
mvn clean install

# Run the Spring Boot app
mvn spring-boot:run

Available Endpoints

Visit: http://localhost:8080/api/monitor/...

What’s Next?

This was just the beginning. The project can be extended with:

• Database storage and pagination
• Real-time dashboards (e.g., using WebSockets)
• Alerts when usage thresholds are crossed
• Frontend UI with charting libraries

Final Thoughts

Learning Quartz with this hands-on project taught me more than just scheduling. It gave me insight into:

• Modular Spring Boot design
• Background job patterns
• Building developer tools that solve real problems

This was more than an experiment — it was a stepping stone into backend systems that are time-sensitive and efficient.

Let me know if you want to contribute to the project.

Happy Learning!