Kim Young-han's Practical Java - Advanced Part 2, I/O, Network, Reflection

"A query that ran perfectly during development suddenly slows down as data accumulates." At such times, the mark of a truly skilled developer is identifying the root cause based on solid evidence rather than guesswork, and optimizing a 30-second query down to 0.1 seconds. Master the core principles of database performance—from execution plans, indexes, and optimizers to joins and sorting—using millions of rows of real-world data. Elevate your skills and become a top-tier developer capable of independently analyzing and resolving slow queries in production environments.

Solve the challenges you inevitably face in real-world design—such as common codes, category hierarchies, history tracking, soft deletes, statistics, dynamic design, and JSON utilization—with 9 core patterns. This is not just simple theory; it contains practical know-how and selection criteria for various scenarios, proven across numerous projects. Now, become a true design expert who can confidently handle any requirement that comes your way.

Learn the fundamentals of SQL and databases essential for practical work. Not only developers, but also planners and data analysts can learn SQL in depth.

You will systematically learn database design through three stages—conceptual, logical, and physical—and strengthen your skills through a practical shopping mall project. Gain real-world know-how through modern design techniques and the latest trends.

Learn practical core Java object-oriented concepts easily via example code.

This is a Java course for those who are new to programming. You can easily learn Java by following along with the code.

Learn Java generics and collection frameworks in depth with a focus on practical applications. Also learn the basics of data structures.

This book provides an in-depth study of various intermediate-level Java features necessary for practical work, using example code.

This course provides an in-depth study of multithreading and concurrency, from basic principles to practical applications.

Not only developers, but also planners and data analysts learn databases step-by-step, starting from the basics of SQL.

For those who are new to JPA or who use JPA in practice but lack basic theory, By learning the basic theory of JPA solidly, even beginners can confidently use JPA in practice.

Learn the core HTTP features essential for practical use and how to design proper HTTP APIs.

Beginners to Spring can quickly learn the entire Spring web application development process by creating examples.

Spring beginners can grasp core principles and solidify basics via examples.

Learn the essential modern Java technologies of Lambda, Stream, and functional programming with Java, from the basics to the practical level, in depth.

With a practical example, we will design and develop a web application using Spring Boot and JPA. Through this process, you will understand how to use Spring Boot and JPA in practice.

You will learn the core principles and advanced technologies of Spring in depth and be able to use Spring confidently.

Develop APIs using Spring Boot and JPA. And learn how to optimize JPA's extreme performance.

You can understand all the web technologies required for web application development from the basics and complete your learning. In MVC Part 2, you can learn all the practical application techniques needed for real-world web development, building upon the core principles and structures from MVC Part 1.

This course will cover everything you need to know about Spring Boot for practical use.

Learn the essential modern Java technologies of Lambda, Stream, and functional programming with Java, from the basics to the practical level, in depth.

Learn practical core Java object-oriented concepts easily via example code.

Are you using Java but still only utilizing Java 8 syntax? Discover the useful new features added in Java 11 LTS and become a more proficient developer by using Java more conveniently. The features introduced here can be used effectively in Java 11 LTS, 17 LTS, and 21 LTS versions.

For those who are new to JPA or who use JPA in practice but lack basic theory, By learning the basic theory of JPA solidly, even beginners can confidently use JPA in practice.

Through training in thinking, expressing, and coding, you can easily understand and approach Java programming. You can understand the relationship between programming elements and gain confidence in future Java API utilization and projects through precise concept organization of object-oriented programming.

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.

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

Beginners to Spring can quickly learn the entire Spring web application development process by creating examples.

Experience the power of Type Safe SQL with jOOQ!

This course covers essential content that C# application developers with 0.5 to 3 years of experience must know.

Through this course, you can prepare for the AWS Certified Solutions Architect - Associate certification and learn about AWS services in general.

From HTTP basics to data requests, real-time communication, security, and performance optimization, learn the network knowledge web developers must know.

This course is for beginners who have started coding tests but are confused, wondering, “Am I just not good at this, or is there still more I need to learn?” Through easy problems, you will master input processing, strings, data structures, and basic mathematical concepts, while learning the right way to approach problems from the very first step.

Implement a Clash Royale-like game from scratch in Unity using C#. A practical course where even beginners can create character summoning, auto-battles, and wave systems.

This course is a video lecture that systematically covers the core modern JavaScript syntax essential for learning React.js and Vue.js frontend development. It is structured to help you develop efficient coding skills through ES6+ syntax, latest features, and practical examples that can be directly applied to work and learning.

From TCP/IP to HTTP! This course is prepared for those who lack basic network theory but hope to understand major-level concepts, even if it means "memorizing" them. You can do it!

"The Era of Coding with AI: A New Productivity Paradigm for Java Developers" This course is a practical Cursor AI utilization guide for Java developers. Beyond simply copying AI-generated code, you'll learn Vibe Coding methods that maximize development efficiency through collaboration with AI. By leveraging Cursor's powerful code understanding, refactoring, and documentation features, you'll master AI coding workflows step by step that can be immediately applied to real-world projects. In an era where AI writes code for us, "developers who can effectively work with AI" now have the competitive edge. Start your upgraded development experience as a Java developer with this course.

Learn Springboot + Flutter RestAPI Board Creation Faster Than Anyone Develop a CRUD server with Springboot and create your own board with Flutter!!

Through the 25 patterns of OODP, you will learn various ways to design software in an object-oriented manner.

Baekjoon Bronze 4·5 Difficulty Algorithm Beginner Roadmap Starting with 3-4 Problems Daily