Executors: How to synchronously wait until all tasks have finished if tasks are created recursively?

Question

My question is strongly related to this one here. As was posted there, I would like the main thread to wait until the work queue is empty and all tasks have finished. The pr

Answer 1

Java 7 has incorporated support for recursive tasks via its ForkJoinPool executor. It is quite simple to use and scales quite well, as long as the tasks themselves are not too trivial. Essentially it provides a controlled interface that allows tasks to wait for the completion of any sub-tasks without blocking the underlying thread indefinitely.