Java 8 parallelStream & ForkJoinPool

ParallelStreamTest.java

import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ForkJoinPool;
import java.util.stream.Collectors;
import java.util.stream.LongStream;

public class ParallelStreamTest {

    private static boolean verbose = false;
    private static int size = 50;
    private static int sleepTime = 100;


    public static void main(String[] args) throws Exception {

        try {

            stats(ForkJoinPool.commonPool());
            List<Long> list0 = LongStream.rangeClosed(1, size).boxed().collect(Collectors.toList());
            System.out.println("list0:  " + list0);
            System.out.println("");

            Callable<List<Long>> sequentalTask = () -> list0.stream().map(ParallelStreamTest::calculate).collect(Collectors.toList());
            Callable<List<Long>> parallelTask = () -> list0.parallelStream().map(ParallelStreamTest::calculate).collect(Collectors.toList());

            System.out.println("SEQUENTAL TASK:");
            long before = System.currentTimeMillis();
            List<Long> list1 = sequentalTask.call();
            System.out.println("elapsedTime: " + (System.currentTimeMillis() - before));
            System.out.println("list1: " + list1);
            System.out.println("");

            System.out.println("PARALLEL TASK:");
            before = System.currentTimeMillis();
            List<Long> list2 = parallelTask.call();
            System.out.println("elapsedTime: " + (System.currentTimeMillis() - before));
            System.out.println("list2: " + list2);
            System.out.println("");
            stats(ForkJoinPool.commonPool());

            System.out.println("PARALLEL TASK FORK-JOIN POOL:");
            ForkJoinPool threadPool = new ForkJoinPool();
            List<Long> list3 = threadPool.submit(parallelTask).get();
            System.out.println("elapsedTime: " + (System.currentTimeMillis() - before));
            System.out.println("list3: " + list3);
            System.out.println("");
            stats(threadPool);

            System.out.println("SEQUENTAL TASK FORK-JOIN POOL:");
            threadPool = new ForkJoinPool();
            List<Long> list4 = threadPool.submit(sequentalTask).get();
            System.out.println("elapsedTime: " + (System.currentTimeMillis() - before));
            System.out.println("list4: " + list4);
            System.out.println("");
            stats(threadPool);

        } catch (Exception e) {
            System.out.println("" + e);
        }
    }


    private static long calculate(long l){
        try {
        if (verbose) System.out.println("[" + Thread.currentThread().getName() + "] " + l);
            Thread.sleep(sleepTime);
        } catch (InterruptedException e) { /**/ }
        return l * 10;
    }

    private static void stats(ForkJoinPool fjp) {
        System.out.println("availableProcessors: " + Runtime.getRuntime().availableProcessors());
        System.out.println(fjp.toString());
    }

}