Kotlin Tutorial

A modern language on the JVM Kotlin is a statically-typed language created by JetBrains that runs on the Java Virtual Machine. Its design goals are pragmatic: be more concise and ...

Values and variables Prefer val by default and only reach for var when you truly need to reassign — immutable data is easier to reason about. String templates Embed values and ...

Two kinds of types In Kotlin, a type either can hold null or it cannot , and that difference is enforced by the compiler. A plain String can never be null; a String? (with the ...

Classes and constructors Kotlin folds the constructor and property declarations into the class header: val name in the header declares a read-only property and assigns it from the ...

Creating collections Kotlin separates read-only from mutable collections at the type level: Lambdas A lambda is a function you can pass around, written in braces. Inside a ...

The problem with threads Blocking a thread while waiting for network or disk wastes resources, and callback-based async code becomes deeply nested and hard to follow. Kotlin ...