Expert-led training for your team
Kotlin for Advanced Programmers: Take Your Skills to the Next Level

30 August 2023

Kotlin for Advanced Programmers: Take Your Skills to the Next Level

Once you have a solid grasp of Kotlin syntax and basics, it's time to take your skills to an advanced level. This guide will walk you through more sophisticated Kotlin features and techniques used by experienced developers.

We'll cover topics like functional programming, coroutines, generics, DSLs, and Kotlin for multiplatform development. Buckle up - things are about to get more complex!

To get started for you or your team, consider taking JBI Trainings Kotlin Course

Functional Programming in Kotlin

Kotlin supports several functional programming concepts that allow you to write cleaner, more maintainable code:

Higher-Order Functions

These are functions that can take other functions as parameters, or return functions as values. For example:

fun main() { val result = operateOnNumber(5, ::square) println(result) // 25 } fun operateOnNumber(num: Int, operation: (Int) -> Int): Int { return operation(num) } fun square(x: Int) = x * x

Higher-order functions enable passing behavior as parameters.

Lambda Expressions

Lambdas are anonymous functions that can be passed around. For example:

val sum = { x: Int, y: Int -> x + y } println(sum(1, 2)) // 3

Lambdas are concise syntax for utilizing functional concepts.


Marking classes and variables as immutable makes code clearer and safer. Use val instead of var, and copy objects when mutating.

Pure Functions

These are functions that always return the same value for a given input, without side effects. Strive to write pure functions when possible.

Coroutines for Asynchronous Programming

Coroutines allow you to write asynchronous code that looks synchronous. Some examples:

launch { // runs asynchronously } async { // returns a Future } withContext(Dispatchers.IO) { // runs in background thread }

Coroutines simplify async code like making network calls.

Generics in Kotlin

Generics enable reusable code that can work for multiple data types. For example:

class Box<T>(val value: T) fun main() { val stringBox = Box<String>("Text") val intBox = Box<Int>(5) }

The Box class supports any type while ensuring type safety.

DSLs in Kotlin

Kotlin makes it easy to create domain-specific languages (DSLs) with custom syntax. For example, a build configuration DSL:

build { name "My App" dependencies { implementation "org.jetbrains.kotlin:kotlin-stdlib" } }

DSLs provide fluent, readable APIs for specific use cases.

Kotlin Multiplatform

Kotlin Multiplatform allows sharing code between platforms like JVM, JavaScript, and Native. For example:

 expect fun today(): String expect class Date { fun getDayOfMonth(): Int } // Common code fun isLeapYear(year: Int): Boolean 

Write shared logic once, compile everywhere.

Best Practices for Kotlin

Additionally, experienced Kotlin developers follow these best practices:

  • Prefer immutable data by default
  • Use destructuring declarations for complex values
  • Write small functions that do one thing
  • Handle errors with sealed classes instead of exceptions
  • Follow naming conventions like variables in camelCase
  • Add Kotlin docs for public APIs

Following conventions optimizes your Kotlin codebase.

Resources to Level Up on Kotlin

Here are some excellent resources to take your Kotlin skills to advanced levels:

Immerse yourself in these resources to become an expert Kotlin developer.

Use Kotlin in Production Systems

To cement your advanced Kotlin skills, use it to build real production systems:

  • Create Android apps with Kotlin Coroutines + Flow
  • Build backends using Ktor web framework
  • Write Spring applications using Kotlin + Spring Boot
  • Develop desktop apps with TornadoFX or JavaFX
  • Build cross-platform code using Kotlin Multiplatform

Building real-world projects will improve your abilities and give practical experience.

Next Steps on Your Kotlin Journey

With these advanced concepts, you're well on your way towards Kotlin mastery. Some final tips:

  • Read and understand the Kotlin coding conventions
  • Contribute to some open source Kotlin projects
  • Learn about new features in upcoming Kotlin versions
  • Teach Kotlin to others through blogs, talks etc
  • Showcase your Kotlin skills by obtaining certifications

Keep learning, share your knowledge, and enjoy building with Kotlin!


Kotlin is a feature-rich modern language that scales from basics to advanced techniques. This guide gave you a tour of advanced Kotlin - from functional concepts like immutability and coroutines, to leveraging generics, DSLs and multiplatform code. Master these skills to become a well-rounded Kotlin developer.

With these Kotlin basics, you can start tackling real projects. Kotlin has a gentle learning curve while teaching you skills that apply anywhere Java is used. The language improves developer productivity and makes creating applications safer.

Now that you have a Kotlin foundation, you can constantly build on it through practice, taking courses, joining communities and exploring frameworks. Your journey to learn Kotlin has just begun!

Check out our article on How to Get Started with Kotlin: A Step-by-Step Guide for Beginners

In the contemporary landscape of dynamic infrastructure environments, Kotlin emerges as an indispensable asset for both operations teams and developers. Its capacity to eloquently define, create, and manage infrastructure as code establishes a foundation for enhanced efficiency and collaborative infrastructure administration.

Whether initiating an exploration of infrastructure-as-code or enhancing an existing Kotlin-based setup, our comprehensive training modules at JBI Training stand ready to facilitate your mastery of this robust framework. Delay no more; adopt the prowess of infrastructure-as-code to revolutionize your infrastructure workflows without delay.

Initiate your educational journey now with the Kotlin courses at JB International and unlock the boundless potential of infrastructure-as-code at your disposal. Our offerings include:

  • Kotlin: This course is tailored for individuals embarking on their Kotlin journey. Learn the fundamentals of Kotlin programming, understand its syntax, data structures, and object-oriented principles. Acquire the skills necessary to develop efficient and concise code in Kotlin.
  • Kotlin Best Practices: Elevate your Kotlin expertise by delving into best practices. Discover how to write clean, maintainable, and performant Kotlin code. Explore design patterns and idiomatic approaches that optimize your codebase for readability and efficiency.
  • Kotlin Beyond the Basics: Ready to take your Kotlin skills to the next level? This advanced course covers topics such as coroutines, advanced functional programming, and integrating Kotlin with other technologies. Harness the full potential of Kotlin to build sophisticated and robust applications.

Enrol in these courses and embark on a transformative journey to harness the power of Kotlin and infrastructure-as-code. Empower yourself to create, manage, and optimise digital infrastructures with confidence and expertise.

About the author: Daniel West
Tech Blogger & Researcher for JBI Training

+44 (0)20 8446 7555

[email protected]



Copyright © 2023 JBI Training. All Rights Reserved.
JB International Training Ltd  -  Company Registration Number: 08458005
Registered Address: Wohl Enterprise Hub, 2B Redbourne Avenue, London, N3 2BS

Modern Slavery Statement & Corporate Policies | Terms & Conditions | Contact Us


Rust training course                                                                          React training course

Threat modelling training course   Python for data analysts training course

Power BI training course                                   Machine Learning training course

Spring Boot Microservices training course              Terraform training course

Kubernetes training course                                                            C++ training course

Power Automate training course                               Clean Code training course