Java CompletableFuture example

CompletableFutureExample.java

Supplier<List<Integer>> supplier = () -> {
    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    return Arrays.asList(1, 2, 3);
};

Consumer<List<Integer>> consumer = input -> {
    int sum = input.stream().reduce(0, Integer::sum);
    System.out.println("The sum is: " + sum);
};

CompletableFuture<Void> completableFuture = CompletableFuture.supplyAsync(supplier)
        .thenAccept(consumer);

completableFuture.join();