Hands-On High Performance with Spring 5

supplyAsync() – running a task asynchronously, with a return value

When we want to return a result after finishing a task asynchronously, we can use CompletableFuture.supplyAsync(). It takes Supplier<T> as a parameter and returns CompletableFuture<T>.

Let's check the supplyAsync() method by creating another controller method in our BankController class, with the following example:

@RequestMapping(value = "/synccustbal")  @ResponseBody  public CompletableFuture<String> syncCustomerBalance() {    LOGGER.info("Entering in controller");    CompletableFuture<String> completableFuture =     CompletableFuture.supplyAsync(new Supplier<String>() {            @Override      public String get() {        try {          return syncService.syncCustomerBalance().get(); } catch (InterruptedException ...