The essential Kotlin Programming cheat sheet: 7 concise chapters you can read in minutes, distilled from the full deck. When you're ready, drill the flashcards or test yourself under exam conditions.
Kotlin's type system starts with two declarations that differ only in mutability: val creates a read-only reference that cannot be reassigned, while var creates a mutable one. Beyo...
Read full chapter →Null safety is Kotlin's most celebrated feature, designed to eliminate NullPointerException at compile time. By default, types are non-nullable — declaring var name: String means t...
Read full chapter →Kotlin classes are final by default, meaning they cannot be inherited unless explicitly marked open. An open class can be extended, and its members can be overridden with the overr...
Read full chapter →Functions are first-class citizens in Kotlin. A higher-order function is one that takes a function as a parameter or returns one, opening up powerful composition patterns. The func...
Read full chapter →Kotlin's property model unifies simple field access with getter and setter logic. A declaration like val name: String creates a property that the compiler backs with a private fiel...
Read full chapter →Kotlin's collection library distinguishes read-only interfaces from their mutable counterparts. List, Set, and Map describe immutable collections, while MutableList, MutableSet, an...
Read full chapter →Coroutines are Kotlin's framework for writing asynchronous code that looks synchronous. A coroutine is a lightweight, cooperatively scheduled unit of work that can be paused and re...
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