* created for them.
   */
  enum NoRecurse implements Feature<@Nullable Void> {
    SUBMAP,
    DESCENDING;

    @Override
    public Set<Feature<? super @Nullable Void>> getImpliedFeatures() {
      return emptySet();
    }
  }

  /**
   * Creates a suite whose map has some elements filtered out of view.
   *

 *
 */
public class BuildFailure extends BuildSummary {

    /**
     * The cause of the build failure.
     */
    private final Throwable cause;

    /**
     * Creates a new build summary for the specified project.
     *
     * @param project The project being summarized, must not be {@code null}.
     * @param time The build time of the project in milliseconds.

        errorPoms = Set.copyOf(errorPoms);
    }

    /**
     * Creates a successful result with the specified processed and modified POMs.
     */
    public static UpgradeResult success(Set<Path> processedPoms, Set<Path> modifiedPoms) {
        return new UpgradeResult(processedPoms, modifiedPoms, Collections.emptySet());
    }

    /**
     * Creates a failure result with the specified processed POMs and error POMs.
     */

    private Model pom;

    private List<RemoteRepository> repositories = Collections.emptyList();

    private RepositorySystemSession session;

    /**
     * Creates an empty request.
     */
    public DefaultPluginVersionRequest() {}

    /**
     * Creates a request for the specified plugin by copying settings from the specified build session. If the session
     * has a current project, its plugin repositories will be used as well.

    private final Map<MavenProject, Integer> order;

    private final Map<String, MavenProject> projects;

    /**
     * Creates a new project dependency graph based on the specified projects.
     *
     * @param projects The projects to create the dependency graph with
     * @throws DuplicateProjectException
     * @throws CycleDetectedException
     */

package once

// Singleton contains a pointer to T that must be set once.
// Until the value is set all Get() calls will block.
type Singleton[T any] struct {
	v   *T
	set chan struct{}
}

// NewSingleton creates a new unset singleton.
func NewSingleton[T any]() *Singleton[T] {
	return &Singleton[T]{set: make(chan struct{}), v: nil}
}

// Get will return the singleton value.
func (s *Singleton[T]) Get() *T {
	<-s.set
	return s.v

@GwtCompatible
public final class Lists {
  private Lists() {}

  // ArrayList

  /**
   * Creates a <i>mutable</i>, empty {@code ArrayList} instance.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableList#of()} instead.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,
   * use the {@code ArrayList} {@linkplain ArrayList#ArrayList() constructor} directly, taking

            int limit = Integer.parseInt(protoSession.getUserProperties().get(Constants.MAVEN_BUILDER_MAX_PROBLEMS));
            return create(limit, p -> true);
        } else {
            return create(100);
        }
    }

    /**
     * Creates new instance of problem collector with the specified maximum problem count limit,
     * but only preserves problems that match the given filter.
     *

/**
 * Wraps an ordinary {@link URL} as a model source.
 *
 *
 * @deprecated instead use {@link UrlSource}
 */
@Deprecated
public class UrlModelSource extends UrlSource implements ModelSource {
    /**
     * Creates a new model source backed by the specified URL.
     *
     * @param pomUrl The POM file, must not be {@code null}.
     */
    public UrlModelSource(URL pomUrl) {
        super(pomUrl);
    }

  SampleElements<E> samples();

  /**
   * Creates a new container containing the given elements. TODO: would be nice to figure out how to
   * use E... or E[] as a parameter type, but this doesn't seem to work because Java creates an
   * array of the erased type.
   */
  T create(Object... elements);

  /**
   * Helper method to create an array of the appropriate type used by this generator. The returned