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[Lv2] JPA Mastery for Working Developers - From Persistence Context to Practical Patterns

You've probably written SQL using JdbcTemplate before, right? Everyone has likely had that experience of sighing while having to fix both the SQL and the RowMapper every time a single column changes. This course starts from that very pain. Doing a single SELECT with pure JDBC takes 35 lines. You open a Connection, create a PreparedStatement, iterate through the ResultSet, and if you miss a single close(), the server crashes. After typing through this hell yourself, when you finally encounter a single line of JPA's save(), you'll feel "this is why we use JPA" not just in your head, but in your hands.

(5.0) 8 reviews

119 learners

Level Basic

Course period Unlimited

JPA
JPA
spring-jpa
spring-jpa
Java
Java
Spring
Spring
Spring Boot
Spring Boot
JPA
JPA
spring-jpa
spring-jpa
Java
Java
Spring
Spring
Spring Boot
Spring Boot

Reviews from Early Learners

5.0

5.0

Bruce Han

100% enrolled

Great things about this course - It teaches JPA very well with a focus on practical application. - Theories are explained through analogies, which helped me understand them quickly. Points to note when taking the course - You won't remember much if you just listen. That's why I think it's important to listen to one lecture, type along with the materials, and ensure you understand before moving on. Areas for improvement - There are occasional typos in the videos. For example, "polymorphism" is written as "diversity," and there are cases where words like "builder.and" are incorrectly displayed as "builder.end" in the subtitles.

5.0

안승현

61% enrolled

I am enjoying the lectures. Subjectively speaking, this is the easiest course to understand.

5.0

부분적무료화

100% enrolled

It explains JPA very easily and provides a clear explanation of the paradigm mismatch between objects and database tables along with relevant examples. Rather than just listing various JPA features, it recommends specific features to use and those to avoid, providing practical advice on how they are typically used in real-world development. For those already familiar with JPA in a professional setting, it serves as a great refresher course; for those using it for the first time or considering its adoption, it can be used as a guidebook to build services without much difficulty.

What you will gain after the course

  • The ability to fluently explain first-level cache, dirty checking, and transactional write-behind based on hands-on experience.

  • The experience of realizing why JPA is necessary after personally suffering through 35 lines of JDBC code.

  • Practical debugging skills to identify the cause of N+1 problems by analyzing logs and selecting the appropriate solution among Fetch Join, @EntityGraph, or @BatchSize based on the situation.

  • The ability to design clean dynamic queries without "if-statement spaghetti" using QueryDSL's BooleanExpression, and to integrate JPA and QueryDSL into a production-standard structure using the Custom Repository pattern.

  • From entity design to inheritance relationship mapping, BaseEntity (Auditing), and embedded types — the design intuition to decide "Let's go with this pattern" rather than asking "How should I design the table?" when starting a real-world project.

Recommended for
these people

Who is this course right for?

  • Those who want to get a feel for what JPA is and why it should be used.

  • Those who want to induce follow-up questions from interviewers with experience-based answers

  • For those who understand @ManyToOne but are confused about why bidirectional relationships are necessary and what mappedBy actually is.

  • Those who want to understand the principles of when queries are executed, how change detection works, and why there is no need to use update().

  • Those who need the practical ability to read query logs and resolve issues directly.

Need to know before starting?

  • Java Basic Syntax (if statements, for statements, classes, interfaces)

  • Experience building a simple REST API with Spring Boot

  • Experience performing DB CRUD using JdbcTemplate (basics such as SQL SELECT, INSERT, etc.)

Hello
This is dingcodingco

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4.9

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🚀 Former Toss, POSTECH graduate | Current Backend Developer (+9 years)
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📚 Inflearn Instructor | Over 18,000+ cumulative students
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I deliver vivid, real-world industry insights in a way that is easy to understand and logically deductive.
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Curriculum

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41 lectures ∙ (9hr 39min)

Published: 
Last updated: 

Reviews

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8 reviews

5.0

8 reviews

  • brucehan님의 프로필 이미지
    brucehan

    Reviews 97

    Average Rating 4.5

    Edited

    5

    100% enrolled

    Great things about this course - It teaches JPA very well with a focus on practical application. - Theories are explained through analogies, which helped me understand them quickly. Points to note when taking the course - You won't remember much if you just listen. That's why I think it's important to listen to one lecture, type along with the materials, and ensure you understand before moving on. Areas for improvement - There are occasional typos in the videos. For example, "polymorphism" is written as "diversity," and there are cases where words like "builder.and" are incorrectly displayed as "builder.end" in the subtitles.

    • dingcodingco
      Instructor

      I'm delighted to hear that the practical explanations and analogies were helpful. Thank you for meticulously pointing out the typos in the subtitles, and I believe your approach of completing the course by using both the lectures and the textbook will serve as a great reference for other students.

  • tarrot1415님의 프로필 이미지
    tarrot1415

    Reviews 3

    Average Rating 5.0

    5

    100% enrolled

    It explains JPA very easily and provides a clear explanation of the paradigm mismatch between objects and database tables along with relevant examples. Rather than just listing various JPA features, it recommends specific features to use and those to avoid, providing practical advice on how they are typically used in real-world development. For those already familiar with JPA in a professional setting, it serves as a great refresher course; for those using it for the first time or considering its adoption, it can be used as a guidebook to build services without much difficulty.

    • dingcodingco
      Instructor

      I am very glad that the explanation distinguishing between object and DB paradigm differences, as well as recommended and discouraged patterns in practice, was helpful. Thank you for completing the course.

  • abeb30318님의 프로필 이미지
    abeb30318

    Reviews 6

    Average Rating 5.0

    5

    61% enrolled

    I am enjoying the lectures. Subjectively speaking, this is the easiest course to understand.

    • dingcodingco
      Instructor

      Thank you so much for saying that it was easy to understand. I tried to convey the core concepts of JPA as intuitively as possible, and I feel rewarded that it seems to have resonated with you.

  • trixiel님의 프로필 이미지
    trixiel

    Reviews 7

    Average Rating 5.0

    5

    100% enrolled

    I used to just add annotations without really knowing how they worked internally, but by going back and forth between the test code and the actual implementation, I was able to better understand how it works logically and why we use JPA!

    • dingcodingco
      Instructor

      I am truly glad that you understood the principles of operation beyond the annotations. I am grateful that the way I structured it—going back and forth between test code and actual implementation so you could personally experience 'Why JPA'—seems to have been well-conveyed!

  • techietaek님의 프로필 이미지
    techietaek

    Reviews 6

    Average Rating 5.0

    5

    100% enrolled

    This course is designed to introduce and allow you to practice everything from the basics of JPA to production-level code. It doesn't stop at simple usage; by learning the internal working principles, I feel I was able to build an even more solid foundation! Thank you for the excellent lecture!

    • dingcodingco
      Instructor

      I put a lot of effort into diving deep into the internal workings because I believed it would be truly helpful in practice, so thank you for appreciating that. Congratulations on completing the course!

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