@Override
    public synchronized void failed(State from, Throwable failure) {
      assertEquals(from, Iterables.getLast(stateHistory));
      stateHistory.add(State.FAILED);
      assertEquals(State.FAILED, service.state());
      assertEquals(failure, service.failureCause());
      if (from == State.STARTING) {
        try {
          service.awaitRunning();
          fail();
        } catch (IllegalStateException e) {

  static final Exception CHECKED_EXCEPTION = new Exception("mymessage");
  static final Future<String> FAILED_FUTURE_CHECKED_EXCEPTION =
      immediateFailedFuture(CHECKED_EXCEPTION);
  static final RuntimeException UNCHECKED_EXCEPTION = new RuntimeException("mymessage");
  static final Future<String> FAILED_FUTURE_UNCHECKED_EXCEPTION =
      immediateFailedFuture(UNCHECKED_EXCEPTION);

     *     State#TERMINATED TERMINATED}.
     */
    public void terminated(State from) {}

    /**
     * Called when the service transitions to the {@linkplain State#FAILED FAILED} state. The
     * {@linkplain State#FAILED FAILED} state is a terminal state in the transition diagram.
     * Therefore, if this method is called, no other methods will be called on the {@link Listener}.

      equalsTester.addEqualityGroup((Object) null);
      fail("Should fail on null reference");
    } catch (NullPointerException e) {
    }
  }

  /** Test equalObjects after adding multiple instances at once with a null */
  public void testAddTwoEqualObjectsAtOnceWithNull() {
    try {
      equalsTester.addEqualityGroup(reference, equalObject1, null);
      fail("Should fail on null equal object");
    } catch (NullPointerException e) {

import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_CHECKED_EXCEPTION;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_ERROR;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_OTHER_THROWABLE;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_UNCHECKED_EXCEPTION;

    @Override
    public synchronized void failed(State from, Throwable failure) {
      assertEquals(from, Iterables.getLast(stateHistory));
      stateHistory.add(State.FAILED);
      assertEquals(State.FAILED, service.state());
      assertEquals(failure, service.failureCause());
      if (from == State.STARTING) {
        try {
          service.awaitRunning();
          fail();
        } catch (IllegalStateException e) {

        assertThrows(RuntimeException.class, () -> service.startAsync().awaitRunning());
    assertThat(e).hasCauseThat().isSameInstanceAs(exception);
    assertEquals(Service.State.FAILED, service.state());
  }

  public void testFunctionalStop_failed() {
    final Exception exception = new Exception("deliberate");
    AbstractIdleService service =
        new DefaultService() {
          @Override

 *     Guava 27.0
 */
public final class InternalFutures {
  /**
   * Usually returns {@code null} but, if the given {@code Future} has failed, may <i>optionally</i>
   * return the cause of the failure. "Failure" means specifically "completed with an exception"; it
   * does not include "was cancelled." To be explicit: If this method returns a non-null value,
   * then:

    READY,
    NOT_READY,
    DONE,
    FAILED,
  }

  @CheckForNull private T next;

  @CheckForNull
  protected abstract T computeNext();

  @CanIgnoreReturnValue
  @CheckForNull
  protected final T endOfData() {
    state = State.DONE;
    return null;
  }

  @Override
  public final boolean hasNext() {
    checkState(state != State.FAILED);
    switch (state) {
      case DONE:

        case NEW:
        case TERMINATED:
          throw new IllegalStateException("Failed while in state:" + previous, cause);
        case RUNNING:
        case STARTING:
        case STOPPING:
          snapshot = new StateSnapshot(FAILED, false, cause);
          enqueueFailedEvent(previous, cause);
          break;
        case FAILED:
          // Do nothing
          break;
      }
    } finally {