Re: CompletableFuture eventual race condition

11 Jul 2016

      In this program there is a race between the program ending and the
computation trying to print from the daemon thread in the forkjoin pool!

import java.util.concurrent.*;
public class HelloWorld {
    public static void main(String[] args) {
        CompletableFuture.supplyAsync(() -> "Hejjo Worjd from Java")
                         .thenApply(s -> s.replaceAll("j","l"))
                         .thenAccept(System.out::println);
    }
}

Try adding a join:

import java.util.concurrent.*;
public class JoinRace {
    public static void main(String[] args) {
        CompletableFuture.supplyAsync(() -> "Hejjo Worjd from Java")
            .thenApply(s -> s.replaceAll("j","l"))
            .thenAccept(System.out::println).join();
    }
}

On Mon, Jul 11, 2016 at 10:44 AM, Francois Green <francois.green@gmail.com>
wrote:
...
I sorry for posting in list, but I need an authoritative answer.  I was
told by one of the developers of another JVM (Ceylon) language that
CompletableFuture.supplyAsync(() -> "Hejjo Worjd from Java")
        .thenApply(s -> s.replaceAll("j","l"))
        .thenAccept(System.out::println);
would eventual fail to print if run enough times.  Is this true?

Re: CompletableFuture eventual race condition

Martin Buchholz