kotlin-stdlib / kotlin.collections / arrayListOf arrayListOf Common JVM JS Native 1.1 fun <T> arrayListOf(): ArrayList<T> Returns an empty new ArrayList. import kotlin.test.* fun main(args: Array<String>) { //sampleStart val list = arrayListOf<Int>() println("list.isEmpty() is ${list.isEmpty()}") // true list.addAll(listOf(1, 2, 3)) println(list) // [1, 2, 3] //sampleEnd } Common JVM JS Native 1.0 fun <T> arrayListOf(vararg elements: T): ArrayList<T> Returns a new ArrayList with the given elements. import kotlin.test.* fun main(args: Array<String>) { //sampleStart val list = arrayListOf(1, 2, 3) println(list) // [1, 2, 3] list += listOf(4, 5) println(list) // [1, 2, 3, 4, 5] //sampleEnd }