Java Coding Problems

Combining via allOf()

Let's assume that we want to download the following list of invoices:

List<String> invoices = Arrays.asList("#2334", "#122", "#55");

This can be seen as a bunch of independent tasks that can be accomplished in parallel, so we can do it using CompletableFuture as follows:

public static CompletableFuture<String>     downloadInvoices(String invoice) {  return CompletableFuture.supplyAsync(() -> {    logger.info(() -> "Downloading invoice: " + invoice);    return "Downloaded invoice: " + invoice;  });}CompletableFuture<String> [] cfInvoices = invoices.stream()  .map(CustomerAsyncs::downloadInvoices)  .toArray(CompletableFuture[]::new);

At this point, we have an array of CompletableFuture instances, and, therefore, an array of asynchronous ...