Kotlin Fundamentals
Kotlin is a statically typed programming language used for JVM, Android, web, and native applications. Its concise syntax and explicit nullability help you model application code and handle absent values deliberately.
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Intro
Kotlin Fundamentals
Kotlin is a statically typed language with functions, classes, collections, and control flow. You can target the JVM, Android, the web, or native platforms. The language is not a framework: a useful program also needs a target platform, a build setup, and often libraries.
Kotlin's everyday mental model is types plus explicit intent. A type describes the values an expression can hold. val states that a reference cannot be reassigned. var permits reassignment. Type inference can omit a type annotation when the initializer makes the type clear, but the inferred type remains part of the program contract.
fun greeting(name: String): String = "Hello, $name"
val message = greeting("Mina")
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Sources
- https://kotlinlang.org/docs/basic-syntax.html
Supports
- Kotlin applications can use a main function as an entry point
- val cannot be reassigned, var can be reassigned, and Kotlin supports type inference
- Classes can declare constructor properties, classes are final by default, and open permits inheritance
- Kotlin supports lambda-based filter and map collection operations
- https://kotlinlang.org/docs/null-safety.html
Supports
- Kotlin distinguishes nullable and non-nullable types
- Safe calls return null for null receivers and Elvis expressions select an alternative
- Smart casts can follow null checks, safe casts return null on failure, and non-null assertions can throw on null
- https://kotlinlang.org/docs/collections-overview.html
Supports
- Lists are ordered and can repeat elements, sets hold unique elements, and maps have unique keys and mapped values
- Kotlin collection types have read-only and mutable interfaces
- A mutable collection held by val can still support write operations
- https://kotlinlang.org/docs/functions.html
Supports
- Kotlin functions can be top-level, local, members, or extensions
- https://kotlinlang.org/docs/inheritance.html
Supports
- Kotlin classes and members are final by default, open permits inheritance, and override is explicit
- https://kotlinlang.org/docs/coroutines-overview.html
Supports
- Suspending functions can pause and resume without blocking a thread
- Most coroutine features are provided by kotlinx.coroutines and builders run from a CoroutineScope
- https://kotlinlang.org/docs/coroutines-basics.html
Supports
- Documented coroutine work requires a suspending function, a scope, a builder, and a dispatcher
- https://github.com/Heapy/awesome-kotlin
Supports
- Awesome Kotlin is a curated Kotlin ecosystem list; no entry was included without a verified project destination