Kotlin Tutorial · Kotlin Projects · Lesson 31 of 31
Kotlin Next Steps
Where to go after this tutorial: idiomatic Kotlin, Android with Compose, coroutines in depth and related courses.
What you've learned
Variables and types, null safety, functions and lambdas, classes, data and sealed classes, extensions, collections and sequences, scope functions, generics, error handling, delegation, coroutines, Flow, context parameters and testing.
Keep going
- Work through Kotlin Koans and the official docs at kotlinlang.org.
- Build an Android app with Jetpack Compose: the Android with Kotlin and Jetpack Compose course on this site goes from layouts to state, navigation, Room and production releases.
- Build a REST API with Ktor or Spring Boot, using coroutines end to end.
- Read the coroutines guide and test suspending code with
kotlinx-coroutines-test.
fun main() {
val topics = listOf("null safety", "data classes", "sealed types", "extensions", "collections",
"scope functions", "generics", "coroutines", "flow")
println("You covered ${topics.size} core topics:")
println(topics.joinToString(" -> "))
}
Output
You covered 9 core topics: null safety -> data classes -> sealed types -> extensions -> collections -> scope functions -> generics -> coroutines -> flow
Run this on your computer — see “Get Started” for setup.
Test yourself
Which UI toolkit is the default for new Android apps written in Kotlin?
XML layouts onlyJetpack ComposeSwiftUIJavaFX
Show answer
Answer: Jetpack Compose