CompletableFuture exception wrapping

KT24481.kt

import java.util.concurrent.*

fun main(args: Array<String>) {
    class DomainSpecificException : RuntimeException()

    val cf1 = CompletableFuture<Int>()
    val cf2 = CompletableFuture<Int>()
    val res = cf1.thenCompose { cf2 }

    cf1.whenComplete { _, err -> println("cf1: Completed with error = $err") }
    cf2.whenComplete { _, err -> println("cf2: Completed with error = $err") }
    res.whenComplete { _, err -> println("res: Completed with error = $err") }

    cf2.completeExceptionally(DomainSpecificException())
    cf1.complete(239)
}