return null;
    }

    private static final long serialVersionUID = 0;
  }

  /**
   * Returns a view of the elements of {@code unfiltered} that satisfy a predicate. The returned
   * multiset is a live view of {@code unfiltered}; changes to one affect the other.
   *
   * <p>The resulting multiset's iterators, and those of its {@code entrySet()} and {@code

    if (comparator != null) { // can't use ? : because of javac bug 5080917
      return comparator;
    }
    return (Comparator<E>) Ordering.natural();
  }

  /**
   * Returns a live {@link Map} view whose keys are the contents of {@code set} and whose values are
   * computed on demand using {@code function}. To get an immutable <i>copy</i> instead, use {@link
   * #toMap(Iterable, Function)}.
   *

        return set1.contains(element) ^ set2.contains(element);
      }
    };
  }

  /**
   * Returns the elements of {@code unfiltered} that satisfy a predicate. The returned set is a live
   * view of {@code unfiltered}; changes to one affect the other.
   *
   * <p>The resulting set's iterator does not support {@code remove()}, but all other set methods

    public void clear() {
      multimap.clear();
    }
  }

  /**
   * Returns a multimap containing the mappings in {@code unfiltered} whose keys satisfy a
   * predicate. The returned multimap is a live view of {@code unfiltered}; changes to one affect
   * the other.
   *
   * <p>The resulting multimap's views have iterators that don't support {@code remove()}, but all

 */
@Experimental
public class LookupException extends MavenException {

    public LookupException(String message) {
        super(message);
    }

    /**
     * @param message the message to give
     * @param e the {@link Exception}
     */
    public LookupException(String message, Exception e) {
        super(message, e);
    }

    /**
     * @param e the {@link Exception}
     */

                artifacts, rootArtifact, managedVersions, collectionRequest, source, collectionFilter, listeners, null);

        // We have metadata retrieval problems, or there are cycles that have been detected
        // so we give this back to the calling code and let them deal with this information
        // appropriately.

        if (result.hasMetadataResolutionExceptions()
                || result.hasVersionRangeViolations()

    node.thread = null; // mark as 'deleted'
    restart:
    while (true) {
      Waiter pred = null;
      Waiter curr = waiters;
      if (curr == Waiter.TOMBSTONE) {
        return; // give up if someone is calling complete
      }
      Waiter succ;
      while (curr != null) {
        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.

        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5);
    assertMapEquals(
        ImmutableMap.of(
            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6),
        "one",

    }

    /**
     * Creates a string with all location details for the specified model problem. If the project identifier is
     * provided, the generated location will omit the model id and source information and only give line/column
     * information for problems originating directly from this POM.
     *
     * @param problem The problem whose location should be formatted, must not be {@code null}.

        //
        // The request has not set any local or remote repositories as the system scoped dependency being resolved
        // should only
        // give us the dependency off the disk and nothing more.
        //
        request = new ArtifactResolutionRequest()
                .setArtifact(artifact)
                .setResolveRoot(true)