java download multiple files using threads

Question

I am trying to download multiple files that matches a pattern using threads. The pattern could match 1 or 5 or 10 files of diff sizes.

lets say for simplicity sake

Answer 1

All the Above mentioned approach creates Threads but the actual Concurreny is not achieved.

ExecutorService pool = Executors.newFixedThreadPool(5);
final File folder = new File("YOUR_FILES_PATH");
int l = folder.listFiles().length;
System.out.println("Total Files----"+folder.listFiles().length);
long timeStartFuture = Calendar.getInstance().getTimeInMillis();
    pool.execute(new DownloadFile(folder,0,l/2));
    pool.execute(new DownloadFile(folder,(l/2),l));
    pool.shutdown();
    try {
        pool.awaitTermination(Long.MAX_VALUE, TimeUnit.MILLISECONDS);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    long timeEndFuture = Calendar.getInstance().getTimeInMillis();
    long timeNeededFuture = timeEndFuture - timeStartFuture;
    System.out.println("Parallel calculated in " + timeNeededFuture + " ms");

The above program is used to achieve concurreny and please modify as per your requirement.