Checking in which pool parallel streams are executed

ParallelStream.java

package org.codefx.lab.stream;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ForkJoinPool;
import java.util.function.Consumer;
import java.util.stream.IntStream;

public class ParallelStream {

	public static void main(String[] args) throws InterruptedException {
		doWithStream(stream -> stream.sum());
		doWithStream(stream -> stream.parallel().sum());
		doWithStream(stream -> new ForkJoinPool(8).submit(() -> stream.parallel().sum()));
	}

	private static void doWithStream(Consumer<IntStream> streamExecutor) throws InterruptedException {
		CountDownLatch latch = new CountDownLatch(16);
		streamExecutor.accept(
				IntStream
						.range(0, 16)
						.peek(i -> printThreadName(latch, i))
		);
		latch.await();
		System.out.println("Done!\n");
	}

	private static void printThreadName(CountDownLatch latch, int i) {
		System.out.println(i + ": " + Thread.currentThread().getName());
		latch.countDown();
		try {
			Thread.sleep(100);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

}