delegate().execute(command);
  }

  @Override
  public <T extends @Nullable Object> Future<T> submit(Callable<T> task) {
    return delegate().submit(task);
  }

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

  @Override
  public <T extends @Nullable Object> Future<T> submit(
      Runnable task, @ParametricNullness T result) {

  static final OtherThrowable OTHER_THROWABLE = new OtherThrowable();
  static final Future<String> FAILED_FUTURE_OTHER_THROWABLE =
      immediateFailedFuture(OTHER_THROWABLE);
  static final Error ERROR = new Error("mymessage");
  static final Future<String> FAILED_FUTURE_ERROR = immediateFailedFuture(ERROR);
  static final Future<String> RUNTIME_EXCEPTION_FUTURE =
      UncheckedThrowingFuture.throwingRuntimeException(RUNTIME_EXCEPTION);

    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**
     * The elements to be returned by future calls to {@code previous()}, with the first at the top
     * of the stack.
     */

  REMOVE_OPERATIONS(CollectionFeature.REMOVE_OPERATIONS, SUPPORTS_REMOVE_WITH_INDEX);

  private final Set<Feature<? super List>> implied;

  ListFeature(Feature<? super List>... implied) {
    this.implied = copyToSet(implied);
  }

  @Override
  public Set<Feature<? super List>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited

  public boolean setException(Throwable throwable) {
    return super.setException(throwable);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setFuture(ListenableFuture<? extends V> future) {
    return super.setFuture(future);
  }

  private SettableFuture() {}

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.feature;

import java.util.Map;

import org.apache.maven.api.Constants;
import org.apache.maven.api.annotations.Nullable;

/**
 * Centralized class for Maven Core feature information.
 * Features configured are supposed to be final in a given maven session.
 *
 * @since 4.0.0
 */

            .allowsSelfLoops(true)
            .nodeOrder(ElementOrder.<String>natural())
            .<String, Integer>immutable()
            .build();

    assertThat(emptyNetwork.isDirected()).isTrue();
    assertThat(emptyNetwork.allowsSelfLoops()).isTrue();
    assertThat(emptyNetwork.nodeOrder()).isEqualTo(ElementOrder.<String>natural());
  }

  /**

  /**
   * Creates an empty {@code TreeMultimap} ordered by the natural ordering of its keys and values.
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create() {
    return new TreeMultimap<>(Ordering.natural(), Ordering.natural());
  }

  /**

  static <V extends @Nullable Object> V get(AbstractFuture<V> future)
      throws InterruptedException, ExecutionException {
    return future.getFromAlreadyDoneTrustedFuture();
  }

  static <V extends @Nullable Object> V get(AbstractFuture<V> future, long timeout, TimeUnit unit)
      throws InterruptedException, ExecutionException, TimeoutException {
    checkNotNull(unit);
    return future.getFromAlreadyDoneTrustedFuture();
  }

 * AsyncCacheLoader.asyncLoad}</a> must return a {@code CompletableFuture}. Users of Guava's {@link
 * com.google.common.util.concurrent.ListenableFuture} can adapt between the two {@code Future}
 * types by using <a href="https://github.com/lukas-krecan/future-converter#java8-guava">{@code
 * net.javacrumbs.futureconverter.java8guava.FutureConverter}</a>.
 *
 * <h2>More on {@code CacheBuilder}</h2>
 *