5-Week JPA Challenge: Reproducing Everything from N+1 to the Persistence Context

Step-by-step explanations that even beginners can easily understand make coding tests that once seemed daunting clear and approachable. Learn only what you need and apply it to real problems right away!

No coding skills? No problem! Turn your ideas into real profit in just 4 weeks. Use AI and the latest tools to build a website and an app simultaneously and launch your service right away.

I’ll help you understand the core concepts of Python in 60 minutes! Rather than blindly learning syntax, I focus on why and when to use it.

"I have a backend technical interview in a week. What should I start with?" The secret to answers that make interviewers nod Master the actual answer patterns of successful applicants to Naver, Kakao, Coupang, and Toss in just 3 days!

AI is no longer a choice—it’s a matter of survival. Cut development time from 3 days to 30 minutes, delegate repetitive tasks to AI, and focus on solving more important problems. With AI-native development techniques you can apply immediately in real-world work—not just theory—we’ll show you a surefire way to be recognized at your company as a “developer who excels at AI.”

Beyond using AI just for copy-and-paste tasks, learn how to connect Claude Chat, Cowork, MCP, n8n, Supabase, and Vercel to actually automate repetitive work for non-developer office workers. Set in a fictional company called DingcoLabs, this course walks you through hands-on PM, marketing, sales, customer service, and HR scenarios to build a workflow automation system you can put to use at your company right away.

We are living in an era where AI can create 10 files at once. But if you can’t track where the code was changed, it conflicts with your teammates’ code, and you don’t know how to undo it—then no matter how well you use AI, you won’t be productive. This course is not simply a lesson that lists commands like `git add` and `git commit`. It will help you visually understand the principles behind safely managing the code AI produces and merging your code with your teammates’ code. Two hours from now, you’ll be a developer who can freely track, undo, and merge any code—whether it was created by AI or written by you.

In a world where every résumé looks similar, “differentiation” gets you hired. Over six weeks, learn four practical résumé strategies directly from a backend professional.

A 75-minute session for those who have built REST APIs with Spring but are unfamiliar with AWS serverless. We’ll clarify what Lambda, SQS, DLQ, S3, and DynamoDB each are and aren’t responsible for, and directly observe how messages are redelivered and isolated in a DLQ. Hands-on exercises are conducted locally without an AWS account.

You’ve written SQL with JdbcTemplate before, right? I’m sure everyone has experienced the frustration of having to modify both the SQL and the RowMapper every time a single column changes. This course begins with that pain. A single SELECT using plain JDBC takes 35 lines. You open a Connection, create a PreparedStatement, iterate through the ResultSet, and if you forget even one close(), the server goes down. After typing through this hell yourself, encountering JPA’s one-line save() makes you feel, not just understand, “This is why people use JPA.”

When you ask AI, “Give me the top 10 by sales,” it can instantly whip up a plausible-looking query. But to judge whether that query is correct, whether the result of joining three tables is accurate, or whether it’s doing a full scan of 500,000 rows without an index —you ultimately need a solid grasp of database fundamentals. This course doesn’t cover anything difficult. In just two hours, you’ll type along and learn the full flow of SQL, covering only what you need to know before asking AI to do it for you. By the end of the course, you won’t feel uneasy anymore when faced with a query written by AI.

This is an introductory backend development course where you learn through understanding rather than memorization, and through experience rather than theory. Instead of memorizing and reciting a Googled definition in response to the interview question, "What is JPA?", this course helps you give an experience-based answer that begins with, "I've been through JdbcTemplate hell..." You’ll personally experience the process of reducing 30 lines of pure Java ServerSocket code to just 7 lines with Spring Boot, gaining an intuitive understanding of "why we use frameworks." After six lessons, you’ll have a working portfolio project in your hands: a Todo List REST API implemented with Spring Boot + JPA.