Kim Young-han's Practical Java - Intermediate Part 2

"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.

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

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

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.

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.

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

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

You can understand and master all the web technologies required to develop web applications from the basics. You can understand the core principles and structure of Spring MVC and grow into a more in-depth backend developer.

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

Solve everything from the basics of querydsl to practical use all at once!

Spring Data JPA goes beyond the limitations of the past and allows you to complete development with just an interface, without implementing classes in the repository, as if by magic. It also provides all the basic CRUD functions that have been developed repeatedly. We will share practical know-how on Spring Data JPA.

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

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

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

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.

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

Learn I/O, networking, reflection, and annotations in depth, from the basics to the practical level. Build a web application server (WAS) directly in Java.

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

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

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

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

While studying Spring Security, you've probably wondered at least once: "I've built the login, but how do I handle authorization?" "How are authentication and authorization implemented in real-world practice?" This course is a practical, project-oriented lecture designed to solve those exact concerns. Instead of just explaining concepts, we implement them exactly as they are used in real services by: 👉 Building on an actual TodoApp project 👉 Integrating with a database 👉 Managing user permissions 👉 Handling validation In particular, I will provide easy, step-by-step explanations for the parts many students find difficult: Method-level authorization Access control within templates Validation using regular expressions Through this course, I will help you confidently say, 👉 "I can actually use Spring Security." 🚀

This is a basic DFS lecture that explains the way a liberal arts major and working developer studied to get a job :) We have prepared a lecture where you can learn by solving problems yourself, with minimal boring theory lectures! After taking this lecture, you will be able to solve silver level DFS problems on your own according to Baekjoon standards.

JAVA is a programming language, just like the C language. JAVA can be used for web development and application development, and here we will learn JAVA before doing web development.

This lecture covers how to properly implement a linked list-based linear data structure using C language. You can understand the structure of the DB as well as the linked list at once.

In [Java Practical Project: UI Edition], we will create a movie information application that operates solely on pure Java technology using JavaFX. This course is designed to help you deeply understand the "structure connecting screens and logic" by directly implementing UI event handling, asynchronous logic, and user interaction flows in Java before moving on to web and smartphone apps. You will train your structural thinking by separating business logic and UI through integration with Spring Core, and learn how to solve UI performance degradation issues that may occur when fetching movie information from external APIs using asynchronous processing. Through this, you will clearly understand the principles of data flow, event listeners, and thread-based asynchronous processing, elevating your understanding of the Java language itself to the next level. In short, this course is a "practical stage to experience the essence of UI and the core of asynchronous processing with Java before moving to the web." Do not forget that this is not a class for just typing along with code, but a learning experience where you can personally master the principles of connecting UI and logic.

This is a basic DFS lecture that explains the way a liberal arts major and working developer studied to get a job :) We have prepared a lecture where you can learn by solving problems yourself, with minimal boring theory lectures! After taking this lecture, you will be able to solve silver level DFS problems on your own according to Baekjoon standards.

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!

If you use JS but find it difficult to explain why it works, this course provides the answer. From execution context, closures, and the event loop to Promise concurrency, prototypes, Virtual DOM, memory leaks, and bundle optimization—you won't just read about 18 chapters of advanced JS concepts; you'll learn by seeing them happen right before your eyes with a simulator. Code-based quizzes are provided for every chapter, and you can own it for life for the price of a single chicken dinner.

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.

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

Learn to implement Telegram, Slack, KakaoTalk, and Discord bots with Python, exploring each service's features via various examples.

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

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

This is a game development & algorithm course that focuses on the algorithms and principles of 2D game development from the ground up using Windows API and C++.

If you have studied basic grammar, you naturally want to try making something, right? This is a lecture designed to help beginner C++ programmers become proficient in object-oriented programming by creating simple games. We provide the 'minimum' code needed to start game programming on your own and share object-oriented know-how that cannot be mastered through grammar study alone. Have fun creating and quickly leap to an intermediate level or beyond!