AbstractService service, ScheduledExecutorService executor, Runnable task) {
          return new FutureAsCancellable(
              executor.scheduleWithFixedDelay(task, initialDelay, delay, unit));
        }
      };
    }

    /**
     * Returns a {@link Scheduler} that schedules the task using the {@link
     * ScheduledExecutorService#scheduleAtFixedRate} method.
     *

   * identify deadlocks.
   */
  @VisibleForTesting
  static final class Blocker extends AbstractOwnableSynchronizer implements Runnable {
    private final InterruptibleTask<?> task;

    private Blocker(InterruptibleTask<?> task) {
      this.task = task;
    }

    @Override
    public void run() {}

    private void setOwner(Thread thread) {
      super.setExclusiveOwnerThread(thread);
    }

  public void testNoOpScheduledExecutor() throws InterruptedException {
    taskDone = false;
    Runnable task =
        new Runnable() {
          @Override
          public void run() {
            taskDone = true;
          }
        };
    ScheduledFuture<?> future =
        TestingExecutors.noOpScheduledExecutor().schedule(task, 10, MILLISECONDS);
    Thread.sleep(20);
    assertFalse(taskDone);
    assertFalse(future.isDone());

  public void testNoOpScheduledExecutor() throws InterruptedException {
    taskDone = false;
    Runnable task =
        new Runnable() {
          @Override
          public void run() {
            taskDone = true;
          }
        };
    ScheduledFuture<?> future =
        TestingExecutors.noOpScheduledExecutor().schedule(task, 10, MILLISECONDS);
    Thread.sleep(20);
    assertFalse(taskDone);
    assertFalse(future.isDone());

     * Returns whether the task has been canceled.
     *
     * @return whether the task has been canceled
     */
    public boolean isCanceled() {
        return status == CANCELED;
    }

    /**
     * Cancels the task.
     */
    public void cancel() {
        status = CANCELED;
    }

    /**
     * Returns whether the task is stopped.
     *
     * @return whether the task is stopped
     */

# o variousMap    -- The various settings about JDBC task.
#
# *The line that starts with '#' means comment-out.
#
map:{
    ; driver   = org.h2.Driver
    ; url      = jdbc:h2:file:../src/test/resources/dummydb/dummydb
    ; schema   =  
    ; user     = sa
    ; password =  

    # /- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    # o propertiesMap: (NotRequired - Default map:{})

It's called "asynchronous" because the computer / program doesn't have to be "synchronized" with the slow task, waiting for the exact moment that the task finishes, while doing nothing, to be able to take the task result and continue the work.

import org.jspecify.annotations.Nullable;

/**
 * An abstract {@code ScheduledExecutorService} that allows subclasses to {@linkplain
 * #wrapTask(Callable) wrap} tasks before they are submitted to the underlying executor.
 *
 * <p>Note that task wrapping may occur even if the task is never executed.
 *
 * @author Luke Sandberg
 */
@J2ktIncompatible
@GwtIncompatible

    return delegate().submit(task);
  }

  @Override
  public ListenableFuture<?> submit(Runnable task) {
    return delegate().submit(task);
  }

  @Override
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Runnable task, @ParametricNullness T result) {
    return delegate().submit(task, result);
  }

  private volatile @Nullable InterruptibleTask<?> task;

  TrustedListenableFutureTask(Callable<V> callable) {
    this.task = new TrustedFutureInterruptibleTask(callable);
  }

  TrustedListenableFutureTask(AsyncCallable<V> callable) {
    this.task = new TrustedFutureInterruptibleAsyncTask(callable);
  }

  @Override
  public void run() {
    InterruptibleTask<?> localTask = task;
    if (localTask != null) {