The Easiest Concurrency Problem - Race Condition

# Silicon Valley Internship That Won't Get Cut Even in the AI Era & Complete Course on 30 Big Tech System Designs & Open Source Practical Contributions All students who submit course missions can apply for an AI startup internship in Palo Alto, USA, with exemption from document screening and guaranteed interview opportunities. This course involves designing and scaling 30 real-world system designs based on big tech cases including Netflix, Tesla, Meta, and Tinder. Finally, you'll design your own service from architecture → DB → scaling, contribute to an actively operating open source AI coding agent project (achieving 1.8k downloads per week) to complete your portfolio, and finalize your resume.

In this course, you will learn Kotlin syntax, how to safely convert Java projects to Kotlin, and how to code in a Kotlin-like manner. Learn Kotlin based on practical code and use it yourself to enjoy its advantages.

This course does not teach the grammar of C#. It simply uses C# as a tool for designing object-oriented programs. This course covers in depth the essential content that intermediate and higher level programmers need to know, as well as the content that is essential to developing programs that are linked to databases.

Learn the basic data structures of REDIS and examples of practical use of REDIS through redis-cli (command) practice.

Learn the easy and fun story of SQL Server operations from a Microsoft Certified Trainer! We explain core operational technologies that you can learn and use right away, and that are truly needed in the field, step by step so that even beginners can easily understand.

Regardless of the field! This is a lecture that covers the core fundamentals that developers must know in practice in an easy + code-oriented way. I highly recommend this lecture to all junior developers and job seekers who want to grow.

Build a local LLM with RAG-based Q&A system in just 2 hours of hands-on practice using Docker + ollama + R2R framework. (Suitable for in-house/internal Q&A systems, personal portfolios, AI-powered work capabilities, and even commercial services)

Through this course, you can learn about Docker and set up a CI environment.

A new curriculum that incorporates the experiences of working developers using Docker, providing lectures that are different from existing textbooks and lectures. It starts from the fundamental question of why Docker should be used, rather than simple command usage.

I've created a 'Redis Introduction/Practical (Query Performance Optimization)' course that non-majors can easily understand and immediately apply in practice!

Learn SAGA transaction management techniques for maintaining data consistency in distributed environments through hands-on practice. Configure three microservices using Spring Boot and Docker, and implement both Orchestration and Choreography patterns with Kafka and MySQL. Through this course, you can master core concepts that are immediately applicable in real-world scenarios, including distributed transaction operation principles, compensating transaction design, and failure recovery handling.

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

When you're doing backend development, at some point you face this dilemma. As services grow and traffic increases, there comes a moment when simple REST communication and CRUD structures feel limiting. I experienced the same problem in real-world work and went through many trials and errors between performance and structural complexity. The solution I chose in that process was NATS. Its simple configuration based on a single binary, ultra-low latency performance in microseconds, and the fact that it provides just the right amount of essential features for real work—from Pub/Sub to Queue Groups and JetStream—made it a very practical choice in actual service environments. This course is not about listing NATS features. Based on the problems I faced in real work, I explain with code and flow diagrams which situations led me to choose NATS, why, and how I designed the architecture. This is a course designed to help everyone—from those new to messaging systems, to backend developers preparing for jobs, to senior developers contemplating better architectures—understand distributed systems and grow to the next level.

Spring AI + JPA + MySQL Premium Reservation Agent Backend Development with 'Autonomous Behavior' Beyond Chatbots to Agents: The Definitive Guide to Tool Calling and Prompt Engineering

Learning about various communication techniques and understanding their differences helps you develop the ability to select and implement the most appropriate communication method.

In this course, you will be able to create a Reddit website from scratch, step by step.

This course is built from real-world experience designing and deploying production-grade LLM applications on Azure. Rather than focusing on toy examples or isolated notebooks, I guide students through the exact challenges they face when moving from experimentation to real systems: data ingestion, vector storage, service orchestration, cloud deployment, and security. Throughout the course, I break down complex Azure services into clear, practical steps, explain why each architectural decision is made, and show how components work together in a scalable system. Students learn by building, debugging, and deploying a complete LangChain-based application, gaining confidence in solving real infrastructure and application-level problems.

3D Globe Article Service with ThreeJS and SpringAI | Neo + Essential Create your own 3D globe article service using your personal chatbot and ThreeJS!

You can quickly experience the process of deploying a sample e-commerce service to AWS and continuously improving it into a robust and efficient environment.

Create your own visual novel game using React, Javascript, SpringAI, and Springboot. Learn how to make a web-based visual novel game with SpringAI and React! Neo + Essential