AggregateCompletionStage works fine, however if you have code that submits a lot of tasks and one of those throws an exception that may block the other tasks from completing which will turn cause the AggregateCompletionStage to never complete. There shouldn't be any reason we can't eagerly complete the AggregateCompletionStage as calling code can still register new tasks to it that are just ignored. The only drawback is that non error tasks would continue operation after the AggregateCompletionStage value may have already been retrieved, but in this case the error is vastly more important.