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Beginner-friendlyKotlinJetBrains Academy

Atomic Kotlin

Build Kotlin fluency atom by atom—with hands-on lessons and real-world coding practice.

Skill levelBeginner
Time to complete 22 days
Skill levelBeginner
Time to complete 22 days

About this course

Based on the acclaimed Atomic Kotlin book, this in-IDE course teaches modern Kotlin the way professionals write it—clean, clear, and practical.

Start from scratch and progress atom by atom: write real code, test your understanding, and learn with instant IDE feedback and guided hints.

Your result: Kotlin fluency from basics to advanced, with production-ready skills you can use in real projects.

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This course runs directly in your JetBrains IDE

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Content

  1. Hello, World
  2. var & val
  3. Data Types
  4. Functions
  5. if Expressions
  6. String Templates
  7. Number Types
  8. Booleans
  9. Repetition with while
  10. Looping & Ranges
  11. The in Keyword
  12. Expressions & Statements
  13. Summary 1
  1. Objects Everywhere
  2. Creating Classes
  3. Properties
  4. Constructors
  5. Constraining Visibility
  6. Packages
  7. Testing
  8. Exceptions
  9. Lists
  10. Variable Argument Lists
  11. Sets
  12. Maps
  13. Property Accessors
  14. Summary 2
  1. Extension Functions
  2. Named & Default Arguments
  3. Overloading
  4. when Expressions
  5. Enumerations
  6. Data Classes
  7. Destructuring Declarations
  8. Nullable Types
  9. Safe Calls & the Elvis Operator
  10. Non-Null Assertions
  11. Extensions for Nullable Types
  12. Introduction to Generics
  13. Extension Properties
  14. break & continue
  1. Lambdas
  2. The Importance of Lambdas
  3. Operations on Collections
  4. Member References
  5. Higher-Order Functions
  6. Manipulating Lists
  7. Building Maps
  8. Sequences
  9. Local Functions
  10. Folding Lists
  11. Recursion
  1. Interfaces
  2. Complex Constructors
  3. Secondary Constructors
  4. Inheritance
  5. Base Class Initialization
  6. Abstract Classes
  7. Upcasting
  8. Polymorphism
  9. Composition
  10. Inheritance & Extensions
  11. Class Delegation
  12. Downcasting
  13. Sealed Classes
  14. Type Checking
  15. Nested Classes
  16. Objects
  17. Inner Classes
  18. Companion Objects
  1. Exception Handling
  2. Check Instructions
  3. The Nothing Type
  4. Resource Cleanup
  5. Logging
  6. Unit Testing
  1. Extension Lambdas
  2. Scope Functions
  3. Creating Generics
  4. Operator Overloading
  5. Using Operators
  6. Property Delegation
  7. Property Delegation Tools
  8. Lazy Initialization
  9. Late Initialization
  1. AtomicTest
  2. Java Interoperability

Learn with the tools developers use every day

Real-world development environmentZoom
Real-world development environmentZoom
Real-world development environmentZoom
Real-world development environmentZoom

  • Real-world development environment

    Gain practical experience with the tools and workflows you'll use in your career, minimizing the learning curve when transitioning to real-world projects.

  • Project-based learning journey

    Our plugin is built to help you finish real-world coding projects, which you can display in your code portfolio after completion.

  • Collaboration via Git

    Effortlessly track changes and collaborate on projects using Git, an essential tool for programmers in every field.

  • Focused learning

    Enjoy fewer distractions with assignments, code, debugging, and version control all in one window.

Student? Get JetBrains IDEs & hands-on courses — free for the full duration of your studies.

Apply using your school email, student ID, ISIC card, or another official document.

What do you need to start?

1

Install the Free JetBrains Toolbox App

The JetBrains Toolbox App 2.7+ makes setting up your course effortless. Already have a compatible IDE? It will launch it. If not, the app will install the right free IDE for your course.

Learn more about our licences here.

Download
2

Confirm the course launch

Click Launch course and then Allow to open the Toolbox App.

Select Always Allow to skip this confirmation in the future.

To return to the course later, find it in your IDE's recent projects.

Need more help? Check out our guide.

The JetBrains Toolbox App 2.7+ makes setting up your course effortless. Already have a compatible IDE? It will launch it. If not, the app will install the right free IDE for your course.

Learn more about our licences here.

Download

Click Launch course and then Allow to open the Toolbox App.

Select Always Allow to skip this confirmation in the future.

To return to the course later, find it in your IDE's recent projects.

Need more help? Check out our guide.

FAQ and troubleshooting

Yes, you will need the JetBrains Toolbox App and a JetBrains IDE.

But don't worry! Just click the Open course button and then select Allow in the resultant popup to install the JetBrains Toolbox App. We've taken care of all the necessary settings, and the app will handle the rest of the setup for you.

The JetBrains Toolbox App checks which IDE is compatible with your course and whether it is installed on your computer. If you have the necessary IDE installed, the app will open it. If not, JetBrains Toolbox will initiate the installation, prioritizing free community editions.

Yes, the JetBrains Toolbox App is essential even if you already have a JetBrains IDE. It automatically prepares your IDE for studying by installing the essential plugins and updating the IDE if necessary.

Please make sure your version of the JetBrains Toolbox App is 2.6 or newer. To update, open the app and click Update Toolbox App to 2.6.x., or download the latest version here.

Yes! It's 100% free and works with both the free and paid versions of JetBrains IDEs.

If you're a student, apply for the Student Pack to get full access to JetBrains IDEs for the duration of your studies. If not, check if you qualify for a free non-commercial license.

The configuration process may vary depending on the IDE you are using for the course. For detailed instructions, please refer to the Troubleshooting guide.
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