Functional Programming: A PragPub Anthology

A "Simple" Concurrent Programming Problem

Next, we create a thread pool with five threads in it using Java’s ExecutorService, and we submit 10,000 tasks to the service. Each task increments both our normal counter and our atomic counter. The full code snippet follows.

public class ConcurrencyExamples {

  private static int counter = 0;
  private static AtomicInteger atomicCounter =
      new AtomicInteger(0);

  public static void main(String[] args)
      throws InterruptedException {
    ExecutorService executors = Executors.newFixedThreadPool(5);

    for (int i = 0; i < 10000; i++) {
      executors.execute(new Runnable() {
        public void run() {
          counter++;
          atomicCounter.incrementAndGet();
        }
      });
    }

    // Shut ...