I see, well, I can’t speak to it, since I’ve never tried to design concurrency like this. That said, I think there’s one slightly orthogonal consideration that this doesn’t handle, which is Java’s blocking IO. That’s where we can all, you included, benefit from having a form of lightweight thread. Because even in your ForkJoinPool, if you have FW that do blocking IO, they’ll block the thread and the thread count will grow and grow, making things slower (due to thread creation being slow), and using up more memory.