/**
   * @return a {@code ListenableFuture} representing pending completion of the task
   * @throws RejectedExecutionException {@inheritDoc}
   */
  @Override
  <T extends @Nullable Object> ListenableFuture<T> submit(Callable<T> task);

  /**
   * @return a {@code ListenableFuture} representing pending completion of the task
   * @throws RejectedExecutionException {@inheritDoc}
   */
  @Override

            directExecutor());

    // Wait for the first task to be started in the background. It will block until we explicitly
    // stop it.
    blockingCallable.waitForStart();

    // Give the second task a chance to (incorrectly) start up while the first task is running.
    assertThat(future2.isDone()).isFalse();

    // Stop the first task. The second task should then run.
    blockingCallable.stop();

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

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Runnable task, @ParametricNullness T result) {
    return (ListenableFuture<T>) super.submit(task, result);
  }

## Create a task function { #create-a-task-function }

Create a function to be run as the background task.

It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

    public <T> Future<T> submit(Callable<T> task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedCallable.class);
      return inline.submit(task);
    }

    @Override
    public Future<?> submit(Runnable task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedRunnable.class);
      return inline.submit(task);
    }

    @Override

    protected CommonPoolUtil() {
        // nothing
    }

    /**
     * Executes the given task in the common ForkJoinPool.
     *
     * @param task
     *            the task to execute
     */
    public static void execute(final Runnable task) {
        ForkJoinPool.commonPool().execute(() -> {
            final Thread currentThread = Thread.currentThread();

    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);
  }

   * 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);
    }

                    if (logger.isDebugEnabled()) {
                        logger.debug("Add thumbnail task: {}", task);
                    }
                    if (!thumbnailTaskQueue.offer(task)) {
                        logger.warn("Failed to add thumbnail task: {}", task);
                    }
                    return true;
                }
                return false;
            }
        }

# o schema   -- The schema name.
# o user     -- The database user name.
# o password -- The database password.
# o propertiesMap -- The properties that depends on the database.
# 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