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

This is an introductory backend development course where you learn through understanding rather than memorization, and experience rather than theory. Instead of reciting a Googled definition when asked "What is JPA?" in an interview, this course will empower you to give an answer based on experience, starting with "Well, I've been through JdbcTemplate hell..." You will gain a deep, intuitive understanding of "why we use frameworks" by experiencing firsthand how 30 lines of pure Java ServerSocket code shrink down to just 7 lines in Spring Boot. After 6 sessions, you will walk away with a functional portfolio piece: a Todo List REST API built with Spring Boot + JPA.

(5.0) 39 reviews

239 learners

Level Basic

Course period Unlimited

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

mexaen

100% enrolled

It was such a great experience because I was able to learn in detail why I should use Spring and why it works this way. This lecture was so informative and helpful that I'm looking forward to your future courses as well. Thank you for the great lecture.

What you will gain after the course

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

  • Practical Spring Boot + JPA development skills

  • A learning experience of internalizing the "Why"

  • An eye for reading production code

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

If you learn Spring this way, you will fail the interview

You turn on the lecture and just type along.

@RestController attached, @GetMapping attached... Oh, it works? Portfolio complete!

But this is how they ask in the interview

"What is JPA?"

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

You will fail.

"Have you done a Spring Boot project?"

"Yes! I followed along with a YouTube video... but honestly, as for why IoC is necessary..."

You find yourself unable to explain a project you built by copying and pasting.


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

"This is how you use JPA. Just 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 is a transaction necessary?"

"Why do you separate the Controller and the Service?"

People who have only learned the "How" answer like this

"JPA is an ORM... and if you use save(), it gets saved..."

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

It's because they've never experienced it. Since they've never done it without JPA, they don't know why JPA is necessary.


So this lecture gives you "pain" first.

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

If you build a web server using pure Java, it takes 30 lines. You have to write the HTTP response by hand. As a string. You are literally typing "HTTP/1.1 200 OK" yourself.

What happens when you look at Spring Boot after experiencing this pain? It's finished in 7 lines. The exact same thing runs.

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

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

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

✅ What you will learn.

🍽️ Backend concepts understood through a restaurant analogy

  • 3-tier architecture understood through clerk-manager-warehouse keeper

  • Ordering a burger combo to understand transactions (either give both, or give nothing)

  • Singer and Manager analogy for understanding the Proxy Pattern

  • Analogies and explanations that are impossible to forget once you've heard them



🌱 A course truly for beginners

  • "Why are we learning this?" Explanations for every concept starting from the very beginning

  • If you know Java if and for statements, you're OK; even if you don't know Spring Boot, you're OK.

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

  • Step-by-step hands-on curriculum that even non-majors can follow


✨ Features of this course

📌 Constantly asking "Why?"

This course does not end with "do it like this."

Typical lecture: "JPA is an ORM. You can just use save()." (X)


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

Deeply experiencing why a single line of JPA's save() is a revolution

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


📌 "Pain → Salvation" Learning Method

This is not a lecture that simply gives you the answers. It makes you experience the pain on purpose, and then feel the greatness of the solution.

Session 2: Parsing HTTP with 30 lines of ServerSocket vs. finishing with 7 lines of Spring Boot

Session 3: JdbcTemplate SQL + RowMapper hell, JPA save() in one line

Session 4: "I didn't write the code, so why does it work?" ConfusionPerfect understanding through the Proxy Pattern

Period 5: Controller death from overworkingClean structure through 3-tier separation

This experience will enable 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.


📌 Answering techniques that prompt follow-up questions from the interviewer

Lectures that just throw concepts at you and end there, lectures where you have no idea how to actually use the material in an interview… I hated those kinds of lectures the most.

This course connects concepts → hands-on experience → interview answers.
(The image below shows the interview success content from the Backend Resume Differentiation Course)

Recommended for these people

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


I followed along with YouTube, but I can't explain it in an interview
✔ Those who don't understand the principles behind projects made by copy-pasting
✔ Those who want to become developers who can explain "why the code should be written this way"

I want to prepare for interviews and practice at the same time
✔ Those who want to answer common technical interview questions based on "experience"
✔ Those who want to learn Spring Boot through practice rather than theory

🗺️ This course is Lv.1

This course is the starting point. I am building a Backend Developer Roadmap based on this.

Lv.0 Core Database Concepts - Building Foundations Before Starting Spring

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

Lv.2 A Working Developer's Complete Mastery of JPA - From Persistence Context to Practical Patterns

Lv.3 Deployment (AWS, CI/CD) Releasing to the real world, not just localhost

Lv.5~6 Architecture & Practical Projects: Building MSA, DDD, and E-commerce Systems

Starting from this lecture, let's go through it together step by step!

Spring Boot Lv3 Thumbnail

🎁 EVENT 🎁

There are special benefits provided only to those who take the course.

[Lv1] 18 Spring Boot Interview Questions workbook will be provided.

(This workbook is provided as a Notion link!)

We will provide the textbook to the first 100 people who write a course review!

Verify your course review in the community to receive it!

(I have included the instructions on how to verify in the very last lecture __)


🎁 EVENT 2 🎁

If you submit the Google Form through this link,

🎟 We will send you a 15% discount coupon 🎟

🎁 EVENT 3 🎁

Get a 3-month free trial of IntelliJ IDE!

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


Promotion Code: HYUNJOONPARKxJB
Benefit Details: JetBrains Single IDE (e.g., IntelliJ, PyCharm, WebStorm, etc.) 3-month free trial
Expiration Date: Until May 13, 2026
How to Use😀


1. Access the official JetBrains coupon registration page

2. Enter the code and select the desired IDE

3. Check the license issued via email


Precautions:
This code is only available for new JetBrains users.
(Only those with no prior history of using a paid JetBrains license can register)
(You can do this indefinitely by creating a new Google email account)

The person who created this course

Sharing the behind-the-scenes story of reaching the final interviews at Coupang and Yanolja - A 6th-year developer's story of applying to 24 companies [ep 5]

Dingco Dingco (Main Instructor)

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

  • 2022 ~ : Running the coding YouTube channel Dingco Dingco (Featuring various content related to developer employment)

  • 2022 ~ 2023 : Viva Republica Server Developer


  • Never giving up on a student 🦈

  • Operating a developer career-cracking community and organizing offline meetups


Notes before enrollment

If!! you are having even the slightest hesitation before signing up for the course.

Is this the right course for me to take right now?? If you are having doubts, please feel free to contact us anytime via the Open Chat Room!

😍 I will 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! We provide installation methods for each operating system.


Learning Materials

  • Everything will be shared via Notion and PDF!

  • Project code will be shared!

Prerequisite Knowledge and Important Notes

  • Those who have experience learning Java

  • Those with experience in MySQL CRUD


Recommended for
these people

Who is this course right for?

  • Those who know Java basics (if, for, class) but find the idea of building a 'server' with them vague.

  • Those who can get the code running by following YouTube tutorials but can't explain it in an interview.

  • New job seekers intimidated by "Spring Boot and JPA experience preferred" in job postings

  • Those who have read Spring Boot books but struggle with real-world application

  • Those who completed a coding bootcamp but know the "how" without understanding the "why"

Need to know before starting?

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

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

Hello
This is dingcodingco

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Learners

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Reviews

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Answers

4.9

Rating

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Courses

🚀 Ex-Toss, POSTECH graduate | Current Backend Developer (+8 years)
🎥 YouTuber with 20,000 subscribers | Development content creator
📚 Inflearn Instructor | Cumulative 15,000+ students
👥 Running a developer career community (8,000+ members)
🧩 Contributor to various open source projects (Gradle, Spring AI, etc.)
📝 Passed 38 resume screenings and conducted 100+ resume reviews on Kmong (5.0 rating)

I deliver vivid, real-world industry insights in an easy-to-understand and deductive manner.

Inflearn Interview Link!

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Curriculum

All

42 lectures ∙ (9hr 58min)

Published: 
Last updated: 

Reviews

All

39 reviews

5.0

39 reviews

  • sasas님의 프로필 이미지
    sasas

    Reviews 83

    Average Rating 5.0

    5

    31% enrolled

    • mexaen2391님의 프로필 이미지
      mexaen2391

      Reviews 4

      Average Rating 5.0

      5

      100% enrolled

      It was such a great experience because I was able to learn in detail why I should use Spring and why it works this way. This lecture was so informative and helpful that I'm looking forward to your future courses as well. Thank you for the great lecture.

      • derickun님의 프로필 이미지
        derickun

        Reviews 19

        Average Rating 4.9

        5

        100% enrolled

        I think it was a great lecture that allowed me to strengthen my basics once again! Thank you for the great lecture.

        • 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.

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