How should interruption and cancellation work in Java?

I define whether cancellation means no result is needed, work must stop, or external side effects must be compensated; those are different promises. Idempotency matters because interruption can arrive after a remote write but before its response. I observe cancellation latency, tasks that remain active after timeout, and resource release. For structured request work, the owner should bound time and concurrency and join or account for children instead of abandoning invisible background execution.