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[Lv1] Spring Boot You Can 'Explain' in Interviews - Backend Development Answering with Experience

This is a backend development introductory course where you learn through understanding rather than memorization, and experience rather than theory. Instead of answering the interview question "What is JPA?" by reciting a Googled definition, this course enables you to give an experience-based answer that starts with "I've been through JdbcTemplate hell..." You'll directly experience the process of reducing pure Java ServerSocket from 30 lines to Spring Boot's 7 lines, and understand with your whole body "why we use frameworks." After 6 sessions, you'll have in your hands a working portfolio: a Todo List REST API implemented with Spring Boot + JPA.

(5.0) 32 reviews

188 learners

Level Basic

Course period Unlimited

  • dingcodingco
Spring
Spring
Spring Boot
Spring Boot
JPA
JPA
hibernate
hibernate
Spring
Spring
Spring Boot
Spring Boot
JPA
JPA
hibernate
hibernate

Reviews from Early Learners

Reviews from Early Learners

5.0

5.0

창근

33% enrolled

I ended up taking this course almost by force (?) because my company suddenly started using Spring, but looking back, I don't know what I would have done if I hadn't taken it. I wasn't a complete beginner to backend development, as I had experience with NestJS, so I was worried that Spring might feel too heavy or frustrating. However, those worries were completely shattered from the very first lecture. The flow—from Spring's philosophy to its architecture and why it was designed this way—was so smooth that I lost count of how many "Aha!" moments I had. It doesn't just list syntax; it builds the practical intuition and fundamentals needed in the field. Even coming from a NestJS background, it was great to understand Spring by comparing the two. I can confidently say that for those new to Spring, as well as those like me who have experience with other frameworks but have never properly learned Spring, this single course will completely wash away any vague fears you have. It's hard to find a better course than this for solidifying your fundamentals.

5.0

김민구

39% enrolled

This would be great for people who are new to Spring Boot, just learned Java, or learned it a long time ago. Also, Dingcodingco explains really well so it's easy to understand.

5.0

아트로픽

17% enrolled

This is a lecture that helps you clearly understand why you should use Spring! These days, it's essential to know exactly why certain technologies are used, and I feel like I'm learning that thanks to this course.

What you will gain after the course

  • The ability to answer with "experience" in backend interviews

  • Spring Boot + JPA Practical Development Skills

  • A learning experience that embodies the "Why"

  • The ability to read production code

  • The technology stack required by 95% of entry-level backend developer job postings

If you learn Spring this way, you'll fail the interview

I turn on the lecture and follow along.

I slap on @RestController, add @GetMapping... oh, it works? Portfolio complete!

But in interviews, they ask you like this

"What is JPA?"

"Um... with Java, the database... uh... well..."

You'll fail.

"Have you done a Spring Boot project?"

"Yes! I followed along with a YouTube video... but honestly, I don't really understand why IoC is necessary..."

You find yourself unable to explain a project made through copy-pasting.


Most Spring courses only teach "how to use it".

"Just use JPA like this. Call save()."
"For transactions, just add @Transactional."

If you follow along, it works. You can even build a portfolio.

But interviewers ask "why."

"Why do you use JPA?"

"Why do we need transactions?"

"Why do you separate Controller and Service?"

People who only learned "How" answer like this

"JPA is an ORM and... you use save() to save things..."

That's it.There's nothing more to say.

Because they've never experienced it. They've never worked without JPA, so they don't know why JPA is necessary.


That's why this lecture gives you the "pain" first

To properly learn Spring, you shouldn't learn the convenient things first.You need to experience the inconvenient things first.

When you build a web server with pure Java, it's 30 lines. You have to manually write the HTTP response. As a string. You literally type "HTTP/1.1 200 OK" yourself.

After experiencing this pain, when you look at Spring Boot? 7 lines and you're done. The same thing runs.

At this moment, it becomes: "Ah... so this is why we use Spring Boot"

The same goes for JPA. If you connect to a DB without JPA, you have to write SQL strings directly, and the code just to convert query results into Java objects is 50 lines.

This "pain → salvation" experience will make you "a developer who can explain".

✅ Here's what you'll learn.

🍽️ Backend Concepts Understood Through Restaurant Analogies

  • Clerk-Manager-Warehouse Keeper: Understanding 3-Tier Architecture

  • Understanding transactions through ordering a burger set (give both or neither)

  • Understanding the Proxy Pattern through Singers and Managers

  • Analogies and explanations you can't forget once you hear them



🌱 A course truly designed for beginners

  • Every concept explanation starts with "Why are we learning this?"

  • Java if statements and for loops are all you need to know, no Spring Boot knowledge required

  • "Pain → Salvation" Learning Method: You must endure the pain of 30 lines of ServerSocket to realize the greatness of 7 lines of Spring Boot

  • Step-by-step practical exercises that even non-majors can follow


✨ Features of This Course

📌 Endlessly asks "Why?"

This course doesn't end with just "do it this way."

Regular lectures: "JPA is an ORM. Just use save()." (X)


This course: After directly experiencing the 50-line hell of SQL + RowMapper with JdbcTemplate,

You'll viscerally feel why JPA's single line of save() is revolutionary

Every concept starts with "Why was this technology created?" Once you internalize the Why, the How naturally follows.


📌 "Pain → Salvation" Learning Method

This is not a lecture that simply tells you the answer. It deliberately makes you experience the pain, then makes you realize the greatness of the solution.

Session 2: 30 lines of HTTP parsing with ServerSocket Finished in 7 lines with Spring Boot

Lesson 3: JdbcTemplate SQL + RowMapper hell vs JPA save() one line

Period 4: "I didn't write the code, so why does it work?" Confusion → Perfect understanding through proxy pattern

Lesson 5: Controller doing everything and dying from overwork → Clean structure with 3-layer separation

This experience enables you to start your interview answers with "I've actually experienced this myself..."

You will be able to explain Spring, Spring Boot, JPA, and Hibernate.


📌 How to answer in a way that prompts follow-up questions from the interviewer

Lectures that just throw concepts at you and end there, lectures where you don't know how to use them in interviews... I hated those kinds of lectures the most.

This course connects concepts → hands-on experience → interview answers.
(The image below shows interview questions that were covered in the Backend Resume Differentiation Course)

We recommend this for

I know Java basics, but creating a "server" feels vague
✔ Those who know if statements and for loops but don't know what to build with them
✔ Those who want to start step by step from "Hello World"


I followed YouTube tutorials, but I can't explain it in interviews
✔ Those who don't understand the principles behind projects made by copy-pasting
✔ Those who want to become developers who can explain "why it should be coded this way"

I want to prepare for interviews and practice at the same time
✔ Those who want to answer common technical interview questions with "experience"
✔ Those who want to learn Spring Boot through practice, not theory

🗺️ This course is Lv.1

This course is the starting point. I'm building a backend developer roadmap based on this.

Lv.0 Database Core Concepts Building foundations before starting Spring

Lv.1 Introduction to Spring Boot (This Course) Building APIs with Spring, Interview Preparation

Lv.2 Deployment (AWS, CI/CD) Publishing to the real world, not just localhost

Lv.3 Testing: Become a Developer Who Doesn't Shake When Deploying

Lv.5~6 Architecture & Real-world ProjectMSA, DDD, E-commerce System Development

Let's start with this course and go through it step by step together!

Spring Boot Lv3 Thumbnail

🎁 EVENT 🎁

There is a special benefit provided only to those who take the course.

We provide the Lv.0 Database Core Concepts Course Materials

(This problem set will be provided as a Notion link!)


We'll give this problem set to the first 100 people who write a course review!

Please verify your course review in the community and claim it!

(The verification method is written in the very last lecture __)

🎁 EVENT 2 🎁

If you submit the Google form through this link

🎟 We'll give you a 15% discount coupon 🎟

🎁 EVENT 3 🎁

3 months free access to IntelliJ IDE!

To support your development studies, we've prepared special benefits through a collaboration with JetBrains.
You can use IntelliJ for free for 3 months with the promotion code below!


Promotion Code: HYUNJOONPARKxJB
Benefits: JetBrains single IDE (e.g., IntelliJ, PyCharm, WebStorm, etc.) 3-month free subscription
Valid Until: May 13, 2026
How to Use😀😀

1. Access the official JetBrains coupon registration page

2.Enter the code and select your desired IDE

3. Check the license issued to your email


Important Notice:
This code is only available for new users who are using JetBrains for the first time.
(Only those who have never used a paid JetBrains license before can register)
(You can do this infinitely by creating new Google email accounts)

Who created this course

The behind-the-scenes story of making it to final interviews at Coupang and Yanolja - A 6-year developer's job change story across 24 companies [ep 5]

Dingcodingco (Main Instructor)

  • 2021 ~ 2022: S Coding Club Algorithm (data-structure) Tutor

  • 2022 ~ : Operating coding YouTube channel DingCodingCo (featuring various content related to developer job hunting)

  • 2022 ~ 2023: Viva Republica Server Developer


  • Never give up on students 🦈

  • Running a developer job preparation community and organizing offline meetups


Things to Note Before Enrolling

If!! you have even the slightest hesitation before enrolling.

Is this the right course for me right now?? If you're wondering about this, please feel free to contact us anytime through the open chat room!!

😍 I'll do my best to answer your questions 😍

Practice Environment

  • We use IntelliJ. The Community (free) version is perfectly fine.

  • Windows or Mac, it doesn't matter! Installation methods for each operating system are all provided.


Learning Materials

  • I'll share everything with you in Notion and PDF format!

  • I'll share the project code with you!

Prerequisites and Notes

  • Those who have learned Java before

  • Those with MySQL CRUD experience (It's okay if you don't know. Free database training materials provided!)


Recommended for
these people

Who is this course right for?

  • Someone who knows Java basics (if, for, class) but finds it vague how to actually build a 'server' with it

  • Someone who ran the code by following a YouTube tutorial, but can't explain it in an interview

  • Entry-level job seekers intimidated by "Spring Boot, JPA experience preferred" in job postings

  • People who have read Spring Boot books but can't apply them in real-world situations

  • Someone who completed a development bootcamp but only knows "how" without understanding "why"

Need to know before starting?

  • Basic Java syntax level (completing one introductory Java course is sufficient)

  • Database Knowledge (Free educational materials provided when participating in course review event!)

Hello
This is

13,660

Learners

1,412

Reviews

267

Answers

4.9

Rating

16

Courses

🚀 Ex-Toss, POSTECH Alumni | Backend 8 years
🎥 YouTuber with 20k subscribers | Development content creator
📚 Inflearn Instructor | 8,000+ cumulative students
👥 Running a developer career community (8,000+ members)
🧩 Contributor to various open source projects (Gradle, Spring AI, etc.)
📝 Passed 38 resume screenings & 100+ resume coaching sessions on Kmong (5.0 rating)

Flipping the way you code, DingcoDingco. Delivering knowledge that is easy and deductively understood.
Đảo ngược lập trình, Dingco Dingco. Truyền tải kiến thức một cách dễ hiểu và có tính suy luận.

Inflearn Interview Link!

Curriculum

All

42 lectures ∙ (9hr 58min)

Published: 
Last updated: 

Reviews

All

32 reviews

5.0

32 reviews

  • lich11158962님의 프로필 이미지
    lich11158962

    Reviews 2

    Average Rating 5.0

    5

    33% enrolled

    I ended up taking this course almost by force (?) because my company suddenly started using Spring, but looking back, I don't know what I would have done if I hadn't taken it. I wasn't a complete beginner to backend development, as I had experience with NestJS, so I was worried that Spring might feel too heavy or frustrating. However, those worries were completely shattered from the very first lecture. The flow—from Spring's philosophy to its architecture and why it was designed this way—was so smooth that I lost count of how many "Aha!" moments I had. It doesn't just list syntax; it builds the practical intuition and fundamentals needed in the field. Even coming from a NestJS background, it was great to understand Spring by comparing the two. I can confidently say that for those new to Spring, as well as those like me who have experience with other frameworks but have never properly learned Spring, this single course will completely wash away any vague fears you have. It's hard to find a better course than this for solidifying your fundamentals.

    • kmk8422님의 프로필 이미지
      kmk8422

      Reviews 2

      Average Rating 5.0

      5

      39% enrolled

      This would be great for people who are new to Spring Boot, just learned Java, or learned it a long time ago. Also, Dingcodingco explains really well so it's easy to understand.

      • 98shcho0862님의 프로필 이미지
        98shcho0862

        Reviews 2

        Average Rating 5.0

        5

        31% enrolled

        • atrop님의 프로필 이미지
          atrop

          Reviews 1

          Average Rating 5.0

          5

          17% enrolled

          This is a lecture that helps you clearly understand why you should use Spring! These days, it's essential to know exactly why certain technologies are used, and I feel like I'm learning that thanks to this course.

          • kym26750428님의 프로필 이미지
            kym26750428

            Reviews 1

            Average Rating 5.0

            5

            7% enrolled

            It was great to have the opportunity to review things I already knew. I think this would be beneficial for experienced professionals who want to organize their knowledge while working in the field.

            Limited time deal ends in 7 days

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