The Easiest Concurrency Problem - Race Condition

Learn common components of global-scale services through popular papers, books, and articles.

A Java advanced project course for beginner developers who want to develop practical skills! We'll build a console-based kiosk ordering system together using Spring Core, JdbcClient, and H2 DB.

With the arrival of the AI era, the skills required of developers are becoming increasingly complex. You might have thought, "I just need to be good at frontend," but when you try to create your own service or integrate AI features, you eventually hit a massive wall called the backend. However, as you try to start backend development, are you overwhelmed by how much there is to learn—from database design and authentication (Auth) to storage management and complex infrastructure setup? Now, you can lay down that heavy burden. In this course, we use Supabase, which solves all these backend functions at once. We will guide you through the fastest shortcut to becoming a full-stack developer who can "instantly" complete a backend without complex server knowledge and bring ideas to life immediately.

You can learn about the core functions of MySQL and how to effectively use them in your work. You can also gain a new understanding of important parts that you have been using for a long time and have overlooked, and gain in-depth database knowledge.

This is the second lecture following the Database Design Fundamentals course. This is a practical course that focuses on real-world projects from start to finish. After understanding all the lecture content, you will be able to freely design databases.

Many backend developers use Redis, but in reality, they often use it merely as a simple cache server. There are many cases where developers know the Redis data types but don't know how to apply them in practice, lack experience implementing real-world patterns like distributed locks or rate limiting, or fail to understand Redis from a backend architecture perspective. I also had the experience of pondering how to utilize Redis in a high-traffic environment while developing actual services. This is because knowing simple commands is entirely different from solving service problems with Redis. This course starts with the basic concepts and data structures of Redis and progresses through learning by implementing core patterns used in actual backend services step-by-step. In particular, you will learn how to solve the following practical problems using Redis: Caching (Cache-Aside) strategies to reduce server load, Distributed Sessions (Session Store) to share login states, Distributed Locks to solve concurrency issues, Rate Limiting to prevent API overload, and Real-time Ranking Systems (Leaderboards) for large-scale users. All hands-on exercises are conducted in a real API server environment based on Python FastAPI. Rather than just learning simple CLI commands, you will understand how Redis is used in backend systems by implementing it yourself. Through this course, you will be able to utilize Redis not just as a simple cache, but as a core tool for designing backend architecture.

You will learn about domain purchase and deploying a Spring Boot production server using EKS, Docker basics, Kubernetes basics, AWS basics, CI/CD automation through GitHub Actions, ArgoCD, and general DevOps topics such as Prometheus/Grafana, etc.

If you ask an AI to "get the top 10 sales," it will whip up a plausible-looking query in no time. However, to determine if that query is actually correct, if the results of joining three tables are accurate, or if it's performing a full scan on 500,000 records without an index—you ultimately need a foundation in DB basics. This course doesn't cover anything overly difficult. In just 2 hours, you will learn the entire flow of SQL by coding along, covering exactly what you need to know before giving instructions to an AI. By the end of this lecture, you will no longer feel uneasy when faced with a query generated by AI.

I learned it the hard way, but I want you to learn it easily. I've discarded unnecessary theories and included only the core essentials of SQL. Build your SQL confidence quickly.

# Building an 'Intelligent Collaboration' Expert Agent Team Using Spring AI Router Pattern + RAG + MCP Beyond Single Agents to Architecture: The Definitive Guide to Router Pattern and Agent Isolation Design

Learn the SAGA transaction management technique for maintaining data consistency in distributed environments through a hands-on approach. You will configure three microservices using Spring Boot and Docker, and implement both Orchestration and Choreography patterns using Kafka and MySQL. Through this course, you will master core concepts applicable to real-world scenarios, including the operational principles of distributed transactions, designing compensating transactions, and handling fault recovery.

At some point in backend development, you start to have these concerns. It's that moment when services expand and traffic increases, and you begin to feel the limitations of simple REST communication and CRUD structures. I experienced these same issues in the field and went through much trial and error balancing performance and structural complexity. The solution I chose during that process was NATS. Its simple configuration based on a single binary, ultra-low latency performance in microseconds, and the fact that it provides essential features—from Pub/Sub to Queue Groups and JetStream—without being overkill made it a very practical choice for real-world service environments. This course is not just a list of NATS features. Based on the problems I faced in practice, I explain through code and workflows why I chose NATS in certain situations and how I designed the architecture. This course is designed to help everyone—from those new to messaging systems to backend developers preparing for employment and senior developers considering better architectures—understand distributed systems and grow to the next level.

From Docker, Kubernetes to microservices, CI/CD, and service mesh, you can easily learn not only the basic theory but also the actual application implementation through examples. By organizing only the core contents necessary for actual use, it provides a starting point for learning about the element technologies covered in the lecture.

Channel Talk interviewers will directly analyze the difference between failing and passing answers to the same questions, and help you prepare for actual follow-up questions.

I highly recommend Spring AI to developers using Spring Boot and React, as well as those considering the introduction of AI systems in corporate environments. This course goes beyond a simple introduction to libraries; it helps you understand the core concepts and internal structure of Spring AI, and strengthens your practical implementation skills through various hands-on examples. The course is based on Spring AI version 1.1.x and provides continuous technical support and expansion strategies to ensure you can adapt to future version upgrades. Furthermore, we expand the practical value of Spring AI technology by utilizing MCP (Model Context Protocol) to achieve cross-domain context integration, AI linkage in distributed environments, and AI architecture design suitable for enterprise environments. With the goal of building AI systems that can actually be deployed in corporate settings, this will serve as a practical guide that balances theory and hands-on experience.

Developing an AI Safety Report Service with React + Spring AI The 5th Neo + Essential project lecture is about building a Safety Report system, an idea for improving government systems!

SQL data analysis! We will teach you how to solve practical problems that are applicable in the field, quickly and easily!

Learn from the beginning how to set up a development environment that even an ordinary office worker can easily understand. It is practice-oriented and focuses on students learning various development tools such as Vim, VS Code, Git, Docker, and remote development. You can learn how to build an efficient development environment by learning step-by-step from the basic usage of each development tool to advanced functions.

This course proceeds in stages, similar to the actual work, by learning and applying the necessary knowledge while configuring the infrastructure.

Did you give up while studying Spring? Even complete beginners new to coding and non-majors can make it from JSP to Spring Boot without giving up - we'll open the path to Spring Boot for you.