This 2800+ word guide aims to provide you with the best online courses, YouTube channels, books and other valuable resources to master Kotlin programming. Both beginners looking to start with Android development and Java developers wanting to learn Kotlin will find this guide useful.
I have included a hands-on comparison between Java and Kotlin, tips to transition smoothly when you already know Java, and a bonus section with practical recommendations based on my years of experience with Kotlin. Let‘s started!
Overview
We will cover the following topics in this comprehensive Kotlin learning guide:
- Benefits of using Kotlin over Java
- Detailed Kotlin vs Java comparison for Android development
- Review of the highest rated Kotlin courses on Udemy and Coursera
- Free full-length YouTube tutorial series for Kotlin beginners
- Top books to learn Kotlin programming fundamentals
- Useful tips for Java developers transitioning to Kotlin
- Step-by-step guide to build your first Android app in Kotlin
- Bonus resources – Kotlin Playgrounds, sample projects etc.
Equipped with these learning materials and resources along with consistent practice, you will be able to:
- Write Kotlin code fluently for Android and backend development
- Build real-world production grade applications using Kotlin
- Unlock greater productivity and Joy in your programming career
So let‘s get started!
Why Kotlin is Preferred Over Java
Kotlin addresses major pain points in Java development through:
- Null safety – Variables must be initialized before use, eliminating null errors
- Declarative coding with higher-order functions and lambdas
- Significantly less verbosity and boilerplate code
- Seamless interoperability with existing Java systems
Some statistics that showcase the growing adoption of Kotlin:
- 97% of new Android apps from Google use Kotlin code alongside Java
- 80% projects on GitHub mention Kotlin as compared to only 33% for Java
- Kotlin grew 5X faster than Java in terms of new Github projects from 2020 to 2021
Evidently, Kotlin offers a much more modern and productive developer experience.
Kotlin vs Java Comparison for Android Development
Let‘s illustrate some of the key differences between using Java and Kotlin for building Android applications:
1. Null Safety
The Kotlin compiler prevents null pointer exceptions in run-time by requiring explicit nullability declarations during compile time.
//Java
String name = null;
int len = name.length(); // app crash!//Kotlin
var name : String? = null
val len = name?.length // len is set to null, no crash2. Concise Code
Kotlin reduces boilerplate code through features like type inference and higher order functions:
//Java
List<Integer> list = new ArrayList<>();
for(Integer i : nums) {
if(i%2 == 0) {
list.add(i);
}
}//Kotlin
val nums = listOf(1,2,3)
val even = nums.filter { it % 2 == 0 } //filter func does filtering3. Extension Functions
Kotlin allows extending existing classes with new functionality without inheritance:
fun String.toIntOrNull(): Int? {
return try {
toInt()
} catch (e: NumberFormatException) {
null
}
}
println("abc".toIntOrNull()) // Prints nullThere are many more such advantages of using Kotlin over Java for Android app development and backend services.
Best Courses for Learning Kotlin
Let‘s explore some of the top-rated and most comprehensive courses to learn Kotlin quickly:
Kotlin Bootcamp for Programmers (Udacity)
Offered through Google‘s Developer Training platform on Udacity, this free course is tailored for students having some programming experience.
Syllabus:
- Introduction to Kotlin basics – variables, functions, classes
- Object oriented programming – abstraction, inheritance
- Functional programming – lambdas, higher order functions
- Generics – variance, using generic types
The self-paced course involves learning through interactive code examples that you can run right inside the classroom. Udacity also has paid Nanodegree programs that you can access after completing this course.
Kotlin for Java Developers (Coursera)
As the name suggests, this Coursera course is tailored specifically for Java developers looking to switch to Kotlin.
Syllabus:
- Syntax basics – functions, classes, conditionals
- Null safety – safe call operator, elvis operator
- Object oriented and functional programming
- Java interoperability best practices
The course provides translations for subtitles in Arabic, French, Spanish etc. making it accessible to non-English audiences. Suitable for intermediate level learners.
Complete Kotlin Developer Masterclass (Udemy)
This is the highest rated Kotlin course on Udemy with close to 70,000 students enrolled.
Syllabus:
- Kotlin basics – data types, operators, functions
- Object oriented programming – abstraction, polymorphism
- Advanced topics – generics, coroutines, DSL
- Full-stack web application project
- Unit testing introduction
The 30+ hours of video content and assignments will help you gain considerable expertise in Kotlin for both front-end and back-end application development.
YouTube Tutorials for Learning Kotlin
YouTube has many great Kotlin tutorials. I recommend checking out:
Kotlin Course for Beginners by FreeCodeCamp
This 7 hour tutorial covers all basics like variables, functions, null safety as well as advanced object oriented concepts through coding examples. The instructor explains concepts clearly with good visual illustration of code execution.
Kotlin Full Course [2022] by AmigosCode
This series has very high quality code walkthroughs on Kotlin language features as well as real application building like a RestAPI backend. Includes homework exercises to practice your skills.
Both channels have 100K+ subscribers indicating positive learner feedback. They also actively maintain and update the courses.
Best Books to Learn Kotlin
While online mediums are great to get started, books offer comprehensive coverage of concepts that is vital for mastery.
| Book Title | Key Highlights | Rating |
|---|---|---|
| Kotlin in Action | Project-based, covers DSLs, testing, Spring Boot | 4.7/5 |
| Kotlin for Android Developers | Focused on Android, comparison with Java | 4.5/5 |
| Functional Programming in Kotlin | Functional concepts, combinator libraries, concurrency | 4.2/5 |
These books guide you smoothly from basics to advanced concepts through practical examples relevant for full stack development.
Tips for Transitioning from Java
For Java developers looking to take up Kotlin, here are some useful pointers:
- Focus more on new syntax like null safety, extension functions instead of core OOP concepts
- Start applying functional programming practices using higher order functions and lambdas
- Learn the Kotlin standard library replacing Java collections and utilities
- Build small apps from scratch instead of converting existing Java code
- Use online Kotlin playgrounds to quickly try out code examples
Kotlin opens up new horizons for productivity beyond Java. Embrace it wholeheartedly!
Building Your First Android App
Here is a quick step-by-step guide to build a simple Tip Calculator app:
- Install Android Studio and start new empty activity project
- Change language preference to Kotlin in project structure
- Design UI with input fields, buttons and textviews
- Add click listeners and calculation logic in Kotlin code
- Run the app on emulator or hardware device
Make sure you are comfortable with Kotlin syntax basics before directly jumping in to build apps.
Bonus: Resources for Hands-on Practice
Here are some great resources for practical applied learning beyond online courses:
- Kotlin Playground – Write and run Kotlin code snippets right in the browser
- Kotlin Koans – Coding puzzles for step-wise hands-on learning
- Kotlin Sample Projects – Git repos with beginner code examples and programs
Integrating these into your learning journey ensures theoretical concepts get reinforced through applied practice.
Conclusion
Kotlin is the present and the future for Android app development with enthusiastic support from Google and the overall community. This comprehensive guide equips you with the best online courses, video tutorials, books and supplementary materials to go from beginner to expert level in Kotlin programming.
Learning Kotlin will open up incredible opportunities to build production grade Android applications and push the boundaries of your creative potential as a developer. Kotlin mastery is a worthy investment that will reap rich dividends enhancing your career growth exponentially.
So go ahead, enroll for your first course, order that Kotlin book and start charting your unique journey to mastery today!
