getOrDefault

fun <T> Optional<out T & Any>.getOrDefault(defaultValue: T): T(source)

import java.util.Optional

fun main() {
    val present = Optional.of("Hello, world!")
    val absent  = Optional.empty<String>()

    val greeting1 = present.getOrDefault("Hi there")
    val greeting2 = absent.getOrDefault("Hi there")

    println(greeting1) // prints: Hello, world!
    println(greeting2) // prints: Hi there
}