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2026 Coding Test All-in-One [JAVA]

This course is for job seekers and career-changing backend developers preparing for coding tests with JAVA. We clearly identify question types by analyzing 195 actual past exam questions.

(4.9) 28 reviews

303 learners

Level Basic

Course period Unlimited

Java
Java
Coding Test
Coding Test
Algorithm
Algorithm
data-structure
data-structure
Java
Java
Coding Test
Coding Test
Algorithm
Algorithm
data-structure
data-structure

Reviews from Early Learners

Reviews from Early Learners

4.9

5.0

규돌이

100% enrolled

I've completed the entire course. The visual effects and detailed explanations of algorithms I only vaguely understood were extremely helpful for my comprehension. Since the lectures were edited to be compact, I was able to repeatedly watch the difficult parts without feeling time pressure, which was very helpful. I've never left a course review before, but I think this will be a great help for coding tests.

5.0

asdfasdf

19% enrolled

The algorithm principles were explained with illustrations, making them easy to understand and memorable! The materials were also well-organized, which made them great for review.

5.0

gjwnstn515

10% enrolled

I used to study for coding tests alone, just solving problems endlessly, but my skills weren't improving and I kept going in circles, which gradually weakened my motivation. When I tried to start studying again, I didn't feel confident that I could improve my skills by just solving problems alone as before, and I thought I needed a change, so I decided to take this course. While taking the course, starting from the really fundamental concept of time complexity that I should have been thinking about, I realized there were many things I had been missing, and as I addressed these one by one, even the problems I had solved before looked different, and I think it was really great that I could learn how to think about solution methods!

What you will gain after the course

  • Understand internal operating principles 100% perfectly through [Visualization]

  • [4-Step Practical Strategy] that can be used immediately when solving problems

  • How the algorithms I learned are tested [Analysis of 195 Problem Types]

"Take the coding test with Python."

I always give this advice to the many people who seek my consultation. Python has concise syntax. Even for the same logic, the code is shorter. In a coding test environment where every second counts, Python is undoubtedly an "overwhelmingly advantageous weapon." I also passed the Kakao coding test using Python.


But why did I create this grueling 'Java Coding Test Course'? And why are you looking at this page right now, instead of a Python grammar book?

The reason is that it doesn't just end with us 'passing the coding test'. It's because our real goal is to become 'competent backend developers who handle Java and Spring'.


I have met many backend developers at numerous online and offline lecture sites and asked them this question.


"I'm already overwhelmed with studying Spring; do I really need to learn Python syntax from scratch just for coding tests?"

"There are companies where you have to take the test only using Java."

"I'm familiar with Java syntax, but whenever I see a coding test problem, the code gets too long and I feel overwhelmed."


I related to this so much, and while I hesitated because creating a course in Java requires a lot of effort, I finally made up my mind.

"Fine, let's let them compete with the language they are most confident in (JAVA)."

"Instead, let's give them a 'cheat key' that can completely offset Java's disadvantages (long code, complexity)."


That is how this course was born. The time and effort I poured into creating this course were not simply to show you how to solve problems.


First, I was obsessed with 'showing' rather than 'explaining.' An explanation like "a stack is a LIFO structure" would take only 10 seconds to say, but I spent 10 hours creating an animation for it. This was to let you see for yourself how data is stacked in memory and where the pointer moves. Only when you can visualize it in your head will you remain calm when faced with applied problems.


Second, I have prepared 'tools' so that you don't have to start from scratch. Is the Java code too long? Yes, it is. That's why I've prepared 'code templates' that you can copy and use as soon as you enter the exam hall. I have organized the patterns that should come out mechanically as soon as you see the problem, just like formulas.


Third, I have changed the 'order of thinking.' Do you find yourself mindlessly typing on the keyboard only to delete and start over repeatedly? That is not how successful candidates solve problems. They read the hints (Step 1), select an algorithm (Step 2), finish the design (Step 3), and only then do they write the code (Step 4). I will turn this 4-Step thinking process into a habit for you.


This course is a lecture that most efficiently removes the biggest obstacle called the 'coding test' on your journey toward your dream of becoming a backend developer.

If you look at the details below, watch the previews, and see how other coding test lectures explain things, you will clearly realize: there is no other lecture that makes you understand as clearly as this one!


Let's get the coding test out of the way quickly with me and move on to the next step! haha

- Sincerely, Dev Nam No-ssi

A course already taken by over 3,000 students online and offline

I know the algorithm concepts, but I don't know what to do when I actually see a problem.

BFS, DFS, stacks, queues... You've studied them somewhere before, but you're not sure how to actually solve the problems, right?

To be blunt, you don't actually know the concepts!

If you don't understand the internal operating principles of data structures, you will crumble even when faced with slightly modified problems.

👉 Everything will be resolved once you properly understand the internal operating principles.

Coding Test All-in-One [JAVA], here is how it's different.

👉 [Overwhelming Visualization]

How exactly does my code work?

A '100% visualized' lecture that you can see with your own eyes


👉 [4-Step Practical Strategy]

[step 1. Problem Understanding]

[step 2. Approach]

[step 3. Code Design]

[step 4. Code Implementation]

🎉 Special Benefits Exclusive to Students

[🎁 Summary Notes]

- 📘 String Manipulation

- 📘 JAVA for Coding Tests

- 📘 Code Templates

[🎁 Discount Coupon]

- 50% discount coupon for the Bible of Coding Tests

Curriculum Introduction

[Part 1] Introduction to Coding Tests

  • 1-1. How to utilize the Coding Test All-in-One 100%

  • 1-2. Introduction to Coding Tests

[Part 2] Building the Fundamentals

  • 2-1. Data Structures

  • 2-2. Algorithms

  • 2-3. Time Complexity

  • 2-4. Time Complexity Code Examples

  • 2-5. QUIZ #1

  • 2-6. QUIZ #2

  • 2-7. QUIZ 3

  • 2-8. QUIZ No. 4

  • 2-9. QUIZ No. 5

  • 2-10. QUIZ No. 6


[Part 3] Essential Data Structures

  • 3-1. Brute Force Loops

  • 3-2. Array, ArrayList

  • 3-3. Linked List

  • 3-4. Queue

  • 3-5. Stack

  • 3-6. Hash Table

  • 3-7. Hash Set

  • 3-8. [Problem Solving] Problem-solving procedures, explanation lecture structure

  • 3-9. [Problem Solving] Free Event

  • 3-10. [Problem Solving] Correct Parentheses Pairs

  • 3-11. [Problem Solving] Valid Parentheses Pairs

  • 3-12. [Problem Solving] Progressive Overload


[Part 4] Brute Force, Permutations, and Combinations

  • 4-1. Brute Force [Recursion] Basics

  • 4-2. Brute Force [Recursion] Execution

  • 4-3. State Space Tree

  • 4-4. Permutations

  • 4-5. Combinations

  • 4-6. Subsets

  • 4-7. [Problem Solving] Adventure by Accident 1


[Part 5] Graph

  • 5-1. Graph Definition

  • 5-2. traversal

  • 5-3. Breadth-First Search BFS

  • 5-4. Depth-First Search DFS

  • 5-5. DFS, BFS Time Complexity

  • 5-6. [Coding Test TIP] Practical Use of Graphs

  • 5-7. [Coding Test TIP] Question Types

  • 5-8. [Problem Solving] Locked Locker

  • 5-9. [Problem Solving] Red Team Blue Team

  • 5-10. [Problem Solving] Money Exchange 2

[Part 6] Strengthening the Fundamentals

  • 6-1. Grid, Definition of Implicit Graphs

  • 6-2. Implicit Graph Traversal

  • 6-3. Implicit Graph BFS

  • 6-4. Implicit Graph DFS

  • 6-5. [Coding Test TIP] Question Types

  • 6-6. [Problem Solving] Number of Clouds 1

  • 6-7. [Problem Solving] Ambulance Shortest Distance 2


[Part 7] Tree

  • 7-1. Tree Concepts

  • 7-2. Tree Implementation

  • 7-3. Tree Traversal

  • 7-4. Tree BFS

  • 7-5. Tree DFS

  • 7-6. pre-order, in-order, post-order

  • 7-7. [Problem Solving] Infected Folder


Recommended for
these people

Who is this course right for?

  • Backend job seekers or career changers who are much more familiar with JAVA syntax than Python.

  • An applicant planning to apply for a company where the coding test must be taken exclusively in JAVA.

  • Those who are wondering how on earth to apply algorithm concepts to actual problems

Need to know before starting?

  • You only need to know the basic syntax of Java (variables, loops, conditional statements, classes, and functions).

Hello
This is nossi

5,545

Learners

294

Reviews

337

Answers

4.9

Rating

6

Courses

Current CEO of a developer career consulting firm

Guest lecturer for Samsung Electronics employee training
Special lectures for universities, corporations, and government-funded programs

Currently writing a book on interviews (Gilbut Publishing)
Operating the 'Gaebalnam Nossi' YouTube channel

Former Kakao Enterprise

Bachelor's degree in Electronic and Electrical Engineering, Sungkyunkwan University

More

Curriculum

All

69 lectures ∙ (12hr 30min)

Published: 
Last updated: 

Reviews

All

28 reviews

4.9

28 reviews

  • asdfasdfasdf1님의 프로필 이미지
    asdfasdfasdf1

    Reviews 15

    Average Rating 5.0

    Edited

    5

    19% enrolled

    The algorithm principles were explained with illustrations, making them easy to understand and memorable! The materials were also well-organized, which made them great for review.

    • gjwnstn5153010님의 프로필 이미지
      gjwnstn5153010

      Reviews 4

      Average Rating 5.0

      5

      10% enrolled

      I used to study for coding tests alone, just solving problems endlessly, but my skills weren't improving and I kept going in circles, which gradually weakened my motivation. When I tried to start studying again, I didn't feel confident that I could improve my skills by just solving problems alone as before, and I thought I needed a change, so I decided to take this course. While taking the course, starting from the really fundamental concept of time complexity that I should have been thinking about, I realized there were many things I had been missing, and as I addressed these one by one, even the problems I had solved before looked different, and I think it was really great that I could learn how to think about solution methods!

      • aaaa123님의 프로필 이미지
        aaaa123

        Reviews 19

        Average Rating 4.9

        5

        5% enrolled

        I pre-registered and completed my first round, and now I'm going through my second round on Inflearn. Both the lecture materials and videos explain everything with visualized content, making it very easy to learn!!

        • kyudori님의 프로필 이미지
          kyudori

          Reviews 1

          Average Rating 5.0

          Edited

          5

          100% enrolled

          I've completed the entire course. The visual effects and detailed explanations of algorithms I only vaguely understood were extremely helpful for my comprehension. Since the lectures were edited to be compact, I was able to repeatedly watch the difficult parts without feeling time pressure, which was very helpful. I've never left a course review before, but I think this will be a great help for coding tests.

          • yangjinho8269061님의 프로필 이미지
            yangjinho8269061

            Reviews 21

            Average Rating 5.0

            5

            31% enrolled

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