kotlin-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, apply, use, 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.
Packages
Collection types, such as Iterable, Collection, List, Set, Map and related top-level and extension functions.
Helper functions for creating Comparator instances.
Sequence type that represents lazily evaluated collections. Top-level functions for instantiating sequences and extension functions for sequences.