الأخطاء في الشيفرة غير المتزامنة

في هذا الدرس

propagate and handle failures.

الموضوعات المخطط لها

• An exception completes the stage exceptionally; dependent stages are skipped and carry it forward.
• exceptionally(fn): recover with a fallback value.
• handle((v, ex) -> ...): see both result and error; whenComplete observes without changing.
• join() throws CompletionException; get() throws ExecutionException; the cause is wrapped.
• An unobserved failed future loses the error silently; always attach handling or read it.