Coding test top basic problems that are really easy to solve (with Java)

You can review the basic concepts you need to know to prepare for the upcoming coding test and solve algorithm problems using Python and Javascript.

🔥 80 Real Coding Test Problems. 8-Week Bootcamp. 🔥 Weekly Live Sessions + 1:1 Coach Feedback + Actual Past Exam Questions

Algorithm Skill Enhancement Pattern Learning with Baekjoon Bronze 1·2 Difficulty Problems

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.

Build your coding skills by implementing data structures in Java from the ground up.

This course is for those preparing for the CosPro Level 1 exam, covering the COS Pro Level 1 sample problems released by the exam organizer, YBM Net Co., Ltd.

Knowing design patterns will make it easier to learn not only Spring but also many other technologies and programming languages. It will also help you develop more flexible and reusable object-oriented software.

When learning Swift, the iOS programming language, it can be confusing when multiple concepts appear all at once. That's why I created this course with the principle that "when understanding a new concept, only previously learned concepts should be used." So this course is meticulously designed with a sequential structure between concepts, where only one new concept appears at each stage, and no other unfamiliar concepts appear at all. One concept per minute, 180 concepts total. From the basics of variables and constants to understanding memory structure from a CS perspective, and even the latest syntax for asynchronous processing. In 3 hours, you'll learn 180 core concepts in the designed order.

Refactoring is one of the basic skills that a software engineer should have. This course is designed to explain and practice various code smells and refactoring techniques in a more practical way using IntelliJ and Java.

Learn the process of application development/release/update all at once through the Android Brainwashing Classroom. Learn the basics of JAVA and learn the distribution and update process while actually building an Android app. Implement the core functions of In★Gram yourself through practice. You can get started even if you don't know programming.

We present various clean coding techniques.

Through this course, you can learn how to run Java applications more efficiently and effectively solve performance issues that may arise.

This course is a video lecture that systematically covers the core modern JavaScript syntax essential for learning React.js and Vue.js frontend development. It is structured to help you develop efficient coding skills through ES6+ syntax, latest features, and practical examples that can be directly applied to work and learning.

From small projects to practicing structure building! A hands-on, mini-project-based introductory course for those who lack experience in Java object-oriented design and practice. From the basics to structural thinking, improve your skills by implementing a Java application from start to finish.

Through the 25 patterns of OODP, you will learn various ways to design software in an object-oriented manner.

The Code Puzzle Clear Challenge is a 4-week intensive training course based on "Learn to Code 1" in Swift Playgrounds, designed to develop "computational thinking" by giving commands to make a computer move as intended. By solving puzzle missions in each session, participants naturally learn to break down problems into smaller steps (decomposition), recognize patterns to organize repetitive rules using for-loops or functions, and make logical judgments to change actions based on specific situations. Beyond simply finding the right answer, participants reach a level where they can explain and refine "why they solved it this way."

In this course, you will learn Kotlin syntax, how to safely convert Java projects to Kotlin, and how to code in a Kotlin-like manner. Learn Kotlin based on practical code and use it yourself to enjoy its advantages.

We enable you to fundamentally understand and resolve issues where Hangeul appears broken on web pages or in databases, or files contain unknown characters.

In [Java Practical Project: UI Edition], we will create a movie information application that operates solely on pure Java technology using JavaFX. This course is designed to help you deeply understand the "structure connecting screens and logic" by directly implementing UI event handling, asynchronous logic, and user interaction flows in Java before moving on to web and smartphone apps. You will train your structural thinking by separating business logic and UI through integration with Spring Core, and learn how to solve UI performance degradation issues that may occur when fetching movie information from external APIs using asynchronous processing. Through this, you will clearly understand the principles of data flow, event listeners, and thread-based asynchronous processing, elevating your understanding of the Java language itself to the next level. In short, this course is a "practical stage to experience the essence of UI and the core of asynchronous processing with Java before moving to the web." Do not forget that this is not a class for just typing along with code, but a learning experience where you can personally master the principles of connecting UI and logic.

IntelliJ IDEA Conf 2025 is an annual online conference hosted by JetBrains that provides valuable sessions for Java and Kotlin developers. It covers various topics including AI adoption, Spring Boot, Gradle, Kafka, database management, and also shares insights on cloud integration, secure coding, developer performance improvement, and advanced development techniques. This conference is open to both professional and beginner developers, offering opportunities to explore the latest technologies along with productivity tips for writing high-quality code faster.