inflearn logo

CS Interview Preparation Guide: Java Edition – Directly from Channel Talk Interviewers

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.

(5.0) 6 reviews

129 learners

Level Basic

Course period Unlimited

Java
Java
oop
oop
computer-science
computer-science
Java
Java
oop
oop
computer-science
computer-science

Reviews from Early Learners

Reviews from Early Learners

5.0

5.0

우혁준

70% enrolled

Every time I prepared for an interview, I felt stuck on how to structure my answers even though I had a rough idea of the concepts. However, this lecture helped me get a feel for interview preparation. I highly recommend it because it goes beyond just learning Java concepts and provides guidance on the overall best way to answer in an interview. If similar lectures on other concepts are released in the future, I would definitely want to take them..!

5.0

paulryu1998

30% enrolled

Thank you. I now know which parts need further reinforcement.

5.0

조만기

87% enrolled

I feel like I had only been simply memorizing theories like Java and JVM until now. After watching this video, I was able to learn how to study effectively, and it was very helpful.

What you will gain after the course

  • A perfect model answer evaluated by the interviewer

  • The critical difference between a failing answer and a passing answer to the same question

  • Full set of actual interview questions and follow-up question pedigrees from Naver, Kakao, LINE, Coupang, Baemin, Danggeun, Toss, and Unicorn companies (100+ items)

  • Answering skills that make you say "I nailed the interview" instead of "I blew the interview"

🤬 Java interviews—I definitely know the material, so why can't I get the words out?!

I'm Jayon, currently working as a backend engineer and interviewer at Channel Talk, after completing the Woowa Tech Course and working as a backend engineer at several companies. I wasn't someone who was good at interviews from the start, either. In fact, I ranked near the bottom in the Woowa Tech Course mock interviews and even had to have a separate private meeting with the CEO.


GC principles? I knew them. JVM structure? Of course, I had it all organized. But everything changed once I sat down in the interview room.

"Please explain the pros and cons of the JVM." Up to that point, it was fine. I spoke smoothly, just as I had prepared. But the moment the interviewer pointed to one of my answers and asked, "Then why exactly is the performance slow?" my mind went completely blank. I had definitely seen it somewhere. I had even summarized it. But in that moment, sitting right there, I just didn't know what to say.

When I got out of the interview and searched for it on my phone, only to realize, "Ah, it was this..." That feeling of emptiness... I'm sure many of you can relate.


From then on, I started recording and reviewing my interviews. I created "incorrect answer notes" and compared my previous answers with my current ones for the same questions. As I accumulated hundreds of these questions and answers, patterns began to emerge. I started to see which answers convinced the interviewers and which ones invited unnecessary follow-up questions.


It was only after going through this trial and error hundreds of times that I realized: knowing the theory and speaking in an interview are completely different skills. That's why I decided to create a lecture focused solely on "how to answer the questions."

✨ 4 Key Points I Focused on While Creating This Course

This is not a theoretical summary lecture. You can find plenty of lectures or blog posts that summarize "What is JVM." This lecture teaches you, "If an interviewer asks this, answer like this." Each lesson corresponds to a single interview question, breaking down step-by-step how you should respond to that specific question.

We provide a comparative analysis of three levels of answers—Bronze, Silver, and Gold—for the same question. Bronze is a 50-point answer out of 100, Silver is an 80-point answer, and Gold is a 100-point answer. We show you specifically why the outcome can differ between a pass and a fail, even when using the same keywords.

The content is based on actual interview questions from major corporations and unicorn startups. It includes not only the main questions but also the follow-up questions that actually follow. From the main question to the follow-up and the follow-up to that, the lectures are structured exactly how the flow of questions happens in a real interview.

Frequently asked questions are provided as an appendix PDF and are continuously updated.Frequently asked questions not covered in the lecture are provided separately in a PDF, and we plan to keep adding more in the future. Once you purchase, you can continue to receive all updated appendices.

👍 This is perfect for people like you!

Those who can answer the initial question but find their mind going blank when follow-up questions start.

Those who want to know the interviewer's inner thoughts and how they would react to a certain answer.

Those who want to get hired by IT service companies like Kakao, Naver, LINE, and Toss.

🍡 A Sneak Peek

'Please explain the algorithms used in GC. Which algorithm does Java use?' During class

'Please explain Java's concurrency issues.' From the class

'(Follow-up question) What exactly is functional programming?' From the class

Note

  1. The class proceeds on the assumption that you have at least a basic knowledge of Java fundamental theory. The effectiveness of the lecture will be maximized if you have been exposed to concepts such as JVM and GC at least once.

  2. If you happen to come across any parts you don't understand while studying, please feel free to ask questions immediately by utilizing the Q&A board😊


🚨 Be sure to check who the person providing the education is!

If you meet the wrong doctor, you may face death because your illness cannot be cured at that moment. However, death ends with the pain of that instant. But if you meet the wrong teacher and receive the wrong education, you will suffer for the rest of your life.

Due to poor education, you may end up at a company you don't want to work for, receive a lower salary than expected, and suffer for the rest of your life as a result. Not only that, but the poor education you received can be passed down to your children as well.

I believe that education is something that can change a person's life in a truly positive way, but on the other hand, it can also completely ruin a person's life. That is why I believe education carries such a heavy responsibility.

Therefore, please check who the educator is, what kind of person they are, and what path they have taken, and make a careful judgment.

👋 Hello!
I'm finally introducing myself ( ⸝⸝•ᴗ•⸝⸝ )੭⁾⁾

Hello!

I am Jayon, a 5th-year developer working as a backend engineer at Channel Talk.

I completed the 3rd Backend Course of Woowa Tech Course and started my career at a small SI company. My salary was at the minimum level. To escape that situation, I spent a tremendous amount of time preparing for coding tests and interviews. As a result, after passing through Chai Corporation (PortOne), I am currently earning several times my initial salary while managing Channel Talk's core systems, which handle billions of records.

I realized through this process that it is truly difficult to find the right direction when preparing for a job alone. That is why I have been active as a backend mentor at F-Lab, JSCODE, and Fast Campus, and served as a reviewer for the 5th Woowa Tech Course. Through mentoring, I have helped students land jobs at top-tier tech companies (Naver, Kakao, Line, etc.), unicorn startups, and major corporations, and the know-how accumulated during that process is fully contained in this lecture.

Just as I received a lot of help when I was going through difficult and challenging times, I wanted to become someone who could also help many others. I felt the most proud and happy when the value I created through development had a positive impact on other people.

I also run a tech blog, steady-coding, so if you're curious about what kind of developer I am, please feel free to stop by!

Thank you!

🚌 Feeling lost about which order to take the courses in?

Please refer to '[2026] Essential Curriculum for Landing a Backend Developer Job (IT Service Companies)'!

Recommended for
these people

Who is this course right for?

  • Those who want to get hired by IT service companies like Kakao, Naver, LINE, and Toss.

  • Those who want to cram for a Java interview in 3 hours right before the meeting.

  • Those who are curious about frequently asked interview questions and the scoring criteria.

  • Those who want to know the inner thoughts of interviewers, wondering, "What will they think when they hear this answer?"

  • Those who have never done a CS interview before and don't even have a sense of what kind of questions will be asked.

  • Those who can answer the initial question but find their mind going blank when follow-up questions are asked.

Hello
This is jayon0927

1,336

Learners

6

Reviews

5.0

Rating

2

Courses

[Contact]

Go to LinkedIn

Go to Resume

 

[Career]

Current) Channel Corporation - Lv 4. Backend Engineer

Former) Chai Corporation (PortOne) - Backend Engineer

 

[Education]

Current) F-Lab Backend Mentor

Current) JSCODE Backend Mentor

Former) Woowa Tech Course 5th Gen Backend Reviewer & 3rd Gen Backend Graduate

More

Co-instructor

Curriculum

All

46 lectures ∙ (2hr 45min)

Course Materials:

Lecture resources
Published: 
Last updated: 

Reviews

All

6 reviews

5.0

6 reviews

  • whjoon02250801님의 프로필 이미지
    whjoon02250801

    Reviews 1

    Average Rating 5.0

    Edited

    5

    70% enrolled

    Every time I prepared for an interview, I felt stuck on how to structure my answers even though I had a rough idea of the concepts. However, this lecture helped me get a feel for interview preparation. I highly recommend it because it goes beyond just learning Java concepts and provides guidance on the overall best way to answer in an interview. If similar lectures on other concepts are released in the future, I would definitely want to take them..!

    • zkspffh2776님의 프로필 이미지
      zkspffh2776

      Reviews 1

      Average Rating 5.0

      5

      87% enrolled

      I feel like I had only been simply memorizing theories like Java and JVM until now. After watching this video, I was able to learn how to study effectively, and it was very helpful.

      • eunmi21652388님의 프로필 이미지
        eunmi21652388

        Reviews 1

        Average Rating 5.0

        5

        83% enrolled

        The most impressive part was evaluating the answers from an interviewer's perspective, and the appendix PDF seems like it would be great to look over in the waiting room on the day of the interview. It's a great value-for-money lecture!

        • paulryu1998님의 프로필 이미지
          paulryu1998

          Reviews 10

          Average Rating 5.0

          5

          30% enrolled

          Thank you. I now know which parts need further reinforcement.

          • tong76218286님의 프로필 이미지
            tong76218286

            Reviews 1

            Average Rating 5.0

            5

            85% enrolled

            While preparing for interviews, I had only been organizing my thoughts using blogs and GPT, but after taking this course, I realized why I kept getting stuck on follow-up questions. I felt a bit called out during the section comparing Bronze and Gold level answers, thinking, "Ah, I was exactly at the Bronze level" lol. The workload wasn't overwhelming, so I was able to binge-watch it over the weekend, and the appendix PDF seems like it'll be great for a quick skim right before the interview. I have an interview coming up soon, and I think there will be a significant difference between going in after taking this course versus not. Thank you for the great lecture!

            • jayon0927
              Instructor

              Hello Gyeom-dung! I'm so proud to hear that the lecture was helpful 🥰 I hope you pass your interview! :)

          Similar courses

          Explore other courses in the same field!

          Limited time deal

          $46,200.00

          30%

          $51.70