What type of Executor is associated with using Parallel Stream threads in Java?

In Java, Parallel Stream uses ForkJoinPool.commonPool() by default — this is an Executor implementation based on ForkJoinPool. This thread pool is optimized for tasks that can be broken down into subtasks and executed in parallel, which is well-suited for parallel streams.

Example:

List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
int sum = list.parallelStream().mapToInt(Integer::intValue).sum();

Here, the parallel stream uses ForkJoinPool.commonPool() to distribute work among threads.