throws ExecutionException, InterruptedException {

    ConcurrentHashMultiset<String> multiset = ConcurrentHashMultiset.create(map);
    int nThreads = 20;
    int tasksPerThread = 10;
    int nTasks = nThreads * tasksPerThread;
    ExecutorService pool = newFixedThreadPool(nThreads);
    ImmutableList<String> keys = ImmutableList.of("a", "b", "c");
    try {
      List<Future<int[]>> futures = newArrayListWithExpectedSize(nTasks);

     */
    protected ExecutorService newFixedThreadPool(final int nThreads) {
        if (logger.isDebugEnabled()) {
            logger.debug("Initialized executor thread pool: size={}", nThreads);
        }
        return new ThreadPoolExecutor(nThreads, nThreads, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(nThreads),
                new ThreadPoolExecutor.CallerRunsPolicy());
    }

    @Override

     * Interval in milliseconds between crawler thread executions.
     * Used to control the rate at which new crawler threads are started
     * and the frequency of status checks.
     */
    protected long crawlingExecutionInterval = Constants.DEFAULT_CRAWLING_EXECUTION_INTERVAL;

    /**
     * Thread priority for crawler threads.
     * Defaults to normal thread priority.
     */
    protected int crawlerPriority = Thread.NORM_PRIORITY;

                }
            }).start();
        }

        // Signal all threads to start at once
        startLatch.countDown();

        // Wait for all threads to complete
        assertTrue("Threads did not complete in time", doneLatch.await(5, TimeUnit.SECONDS));

        // All threads should fail with the same IOException (project ID is blank)

                }
            }).start();
        }

        // Signal all threads to start at once
        startLatch.countDown();

        // Wait for all threads to complete
        assertTrue("Threads did not complete in time", doneLatch.await(5, TimeUnit.SECONDS));

        // All threads should fail with the same IOException (endpoint is blank)

   *
   * Our usages should at least be *relatively* safe: Typically, threads started by a test are dying
   * at the end of the test, so there is no object state put at risk by stopping the threads
   * abruptly. In other cases, a test may put a thread into an uninterruptible operation
   * intentionally, so there is no other way to clean up these threads. (The better solution,

   *
   * Our usages should at least be *relatively* safe: Typically, threads started by a test are dying
   * at the end of the test, so there is no object state put at risk by stopping the threads
   * abruptly. In other cases, a test may put a thread into an uninterruptible operation
   * intentionally, so there is no other way to clean up these threads. (The better solution,

    assertTrue(thread.isAlive());
  }

  /**
   * Checks that the threads do not terminate within the default millisecond delay of {@code
   * timeoutMillis()}.
   */
  void assertThreadsStayAlive(Thread... threads) throws InterruptedException {
    assertThreadsStayAlive(timeoutMillis(), threads);
  }

  /** Checks that the threads do not terminate within the given millisecond delay. */

     */
    public GenerateThumbnailJob() {
        super();
    }

    /**
     * Sets the number of threads to use for thumbnail generation.
     *
     * @param numOfThreads the number of threads
     * @return this job instance for method chaining
     */
    public GenerateThumbnailJob numOfThreads(final int numOfThreads) {
        this.numOfThreads = numOfThreads;
        return this;
    }

      return; // TODO: b/136041958 - Running very slowly on Windows CI.
    }
    CyclicBarrier barrier =
        new CyclicBarrier(
            6 // for the setter threads
                + 50 // for the listeners
                + 50 // for the blocking get threads,
                + 1); // for the main thread
    ExecutorService executor = newFixedThreadPool(barrier.getParties());