* processing and may run concurrently, for example, if the JVM flag {@code
   * -XX:+ExplicitGCInvokesConcurrent} is used.
   *
   * <p>Whenever possible, it is preferable to test directly for some observable change resulting
   * from GC, as with {@link #awaitClear}. Because there are no guarantees for the order of GC
   * finalization processing, there may still be some unfinished work for the GC to do after this

    manager.stopAsync().awaitStopped();
    assertFalse(manager.isHealthy());
    assertTrue(listener.stoppedCalled);
    assertTrue(listener.failedServices.isEmpty());
    // check that our NoOpService is not directly observable via any of the inspection methods or
    // via logging.
    assertEquals("ServiceManager{services=[]}", manager.toString());
    assertTrue(manager.servicesByState().isEmpty());

   * called multiple times.
   *
   * <p>When this method is called {@link #state()} will return {@link State#STOPPING}, which is the
   * external state observable by the caller of {@link #stopAsync}.
   *
   * @since 27.0
   */
  @ForOverride
  protected void doCancelStart() {}

  @CanIgnoreReturnValue
  @Override
  public final Service startAsync() {

   * processing and may run concurrently, for example, if the JVM flag {@code
   * -XX:+ExplicitGCInvokesConcurrent} is used.
   *
   * <p>Whenever possible, it is preferable to test directly for some observable change resulting
   * from GC, as with {@link #awaitClear}. Because there are no guarantees for the order of GC
   * finalization processing, there may still be some unfinished work for the GC to do after this

        .contains("Exception thrown from implementation: class java.lang.StackOverflowError");
  }

  // Regression test for a case where we would fail to execute listeners immediately on done futures
  // this would be observable from an afterDone callback
  public void testListenersExecuteImmediately_fromAfterDone() {
    AbstractFuture<String> f =
        new AbstractFuture<String>() {
          @Override

    manager.stopAsync().awaitStopped();
    assertFalse(manager.isHealthy());
    assertTrue(listener.stoppedCalled);
    assertTrue(listener.failedServices.isEmpty());
    // check that our NoOpService is not directly observable via any of the inspection methods or
    // via logging.
    assertEquals("ServiceManager{services=[]}", manager.toString());
    assertTrue(manager.servicesByState().isEmpty());

        .contains("Exception thrown from implementation: class java.lang.StackOverflowError");
  }

  // Regression test for a case where we would fail to execute listeners immediately on done futures
  // this would be observable from an afterDone callback
  public void testListenersExecuteImmediately_fromAfterDone() {
    AbstractFuture<String> f =
        new AbstractFuture<String>() {
          @Override