Kim Young-han's Java Tutorial - Your First Step into Java with Code

"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.

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

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

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.

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

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

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

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 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.

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

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

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

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.

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

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

You can understand and perfect the basics of DB data access technology required for backend development. You can understand the principles and structure of Spring DB access technology and grow into a more in-depth backend developer.

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

You can utilize and implement the database data access technologies required for backend development. You will understand the principles and structure of Spring DB access technologies and grow into a more in-depth backend developer.

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.

If you want to create a reactive application based on Spring WebFlux, take Kevin's easy-to-understand Spring Reactive WebApplications course. He will kindly guide you into the world of reactivity. ^^

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

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.

This is a lecture using the only domestic e-government framework and Layered Architecture, which are widely used in practice but not available in Korea. In this lecture, we will learn how to build the backend and server side of web development using the Spring Framework and the e-government standard framework.

This course is based on the concepts learned in the Spring Framework and teaches how to implement web applications. All the learned content is summarized and a final mini-project is conducted. After completing the course, you will be able to immediately perform a real project. It contains a total of 65 lectures and 29 hours and 37 minutes of study time.

This is a Unity C# scripting course for absolute beginners who are learning programming for the first time. It was created by carefully selecting the core grammar necessary for utilizing Unity scripts.

Through this course, you will gain a deep understanding of clean code principles and be able to write clean code based on object-oriented thinking. This course is for anyone curious about clean code and object-orientation, and everyone who truly wants to write good code.

Handling media (video, audio) on the web is now easier than ever! Learn the MediaStream API and WebRTC by following along step by step.

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.

An AI system that grades and reviews your code in just 5 seconds—imagination becomes reality. This course is an all-in-one project curriculum for creating a **'GitHub PR Auto-Analysis and Grading Bot'** using Spring AI. When a student submits an assignment (Pull Request), the server detects it, and the AI analyzes the code changes (Diff). The grading results are then stored in a database, feedback is automatically posted as a GitHub comment, and the student can check their results on a dedicated dashboard. From backend to AI integration and frontend (Vaadin), all with just Java! This is the ultimate introductory guide for any developer who wants to build their own AI service from A to Z.

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

Unity 6.3 LTS Compatible | Introduction to 2D Game Development: Learning Background Scrolling, Score Management, and Saving High Scores

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.

A portfolio-focused course on deploying a React frontend and Spring Boot backend directly to the AWS cloud! This course is helpful for those who want to quickly deploy frontend and backend projects for their portfolio. You will gain the necessary knowledge for deployment through short-term, step-by-step practice, covering everything from server configuration to Docker, domain connection, Nginx, and HTTPS application!

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.

Implement a PvZ-style tower defense in Unity from scratch using C#. A practical course where even beginners can learn to build grid-based character placement, enemy pathing/blocking, and coin management.

This is a lecture for people who are starting development for the first time. It's about programming thinking, which should come before development languages or UI frameworks.