Java 17 - implementing CompletableFuture and handling Handling in Asynchronous Tasks
I've searched everywhere and can't find a clear answer. I'm working with a scenario when using `CompletableFuture` in my Java 17 application. I have several asynchronous tasks that I'm chaining together, and I'm working with an scenario where exceptions thrown in one of the tasks aren't being handled as expected. Here’s a simplified version of my code: ```java import java.util.concurrent.CompletableFuture; public class AsyncExample { public static void main(String[] args) { CompletableFuture.supplyAsync(() -> { if (Math.random() > 0.5) { throw new RuntimeException("Random failure"); } return "Success"; }) .thenApply(result -> { System.out.println(result); return result; }) .exceptionally(ex -> { System.err.println("Caught exception: " + ex.getMessage()); return "Fallback value"; }); // Wait for the async task to complete try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } } } ``` In this example, I expect that if the `RuntimeException` is thrown in the lambda function of `supplyAsync`, the `exceptionally` block should catch it and print the behavior message. However, sometimes the application crashes instead of handling the exception gracefully, and I see the following behavior message in the console: ``` Exception in thread "ForkJoinPool.commonPool-worker-1" java.lang.RuntimeException: Random failure at AsyncExample.lambda$main$0(AsyncExample.java:5) ``` I've verified that the random failure occurs and that the exception handling logic is correctly placed after the `thenApply`. I also attempted to chain another `handle` method before `exceptionally`, but this didn't seem to make a difference. Here’s what I tried: - Ensured all tasks are within the same `CompletableFuture` chain. - Used `.handle()` to grasp both the result and the exception. - Checked the thread pool configuration to make sure it’s not running out of threads. Is there something I'm missing with how `CompletableFuture` handles exceptions? Any insight or suggestions would be greatly appreciated! For context: I'm using Java on Linux. How would you solve this?