Module stdlib

Kotlin Standard Library

The Kotlin Standard Library provides living essentials for everyday work with Kotlin. These include:

  • Higher-order functions implementing idiomatic patterns ([let][kotlin.let], [apply][kotlin.apply], [use][kotlin.io.use], [synchronized][kotlin.synchronized], etc).
  • Extension functions providing querying operations for collections (eager) and sequences (lazy).
  • Various utilities for working with strings and char sequences.
  • Extensions for JDK classes making it convenient to work with files, IO, and threading.

Package kotlin

Core functions and types, available on all supported platforms.

Package kotlin.annotation

Library support for the Kotlin annotation facility.

Package kotlin.collections

Collection types, such as [Iterable][kotlin.collections.Iterable], [Collection][kotlin.collections.Collection], [List][kotlin.collections.List], [Set][kotlin.collections.Set], [Map][kotlin.collections.Map] and related top-level and extension functions.

Package kotlin.comparisons

Helper functions for creating [Comparator][java.util.Comparator] instances.

Package kotlin.concurrent

Utility functions for concurrent programming.

Package kotlin.io

IO API for working with files and streams.

Package kotlin.jvm

Functions and annotations specific to the Java platform.

Package kotlin.properties

Standard implementations of delegates for delegated properties and helper functions for implementing custom delegates.

Package kotlin.ranges

Ranges, Progressions and related top-level and extension functions.

Package kotlin.reflect

Runtime API for Kotlin reflection

Package kotlin.reflect.jvm

Runtime API for interoperability between Kotlin reflection and Java reflection.

Package kotlin.sequences

[Sequence][kotlin.sequences.Sequence] type that represents lazily evaluated collections. Top-level functions for instantiating sequences and extension functions for sequences.

Package kotlin.system

System-related utility functions.

Package kotlin.test

Functions for writing test assertions.

Package kotlin.text

Functions for working with text and regular expressions.