if (ranges.isEmpty()) {
      return ImmutableMap.of();
    }
    RegularImmutableSortedSet<Range<K>> rangeSet =
        new RegularImmutableSortedSet<>(ranges, Range.<K>rangeLexOrdering());
    return new ImmutableSortedMap<>(rangeSet, values);
  }

  @Override
  public ImmutableMap<Range<K>, V> asDescendingMapOfRanges() {
    if (ranges.isEmpty()) {
      return ImmutableMap.of();
    }

    TreeMap<K, V> map = Maps.newTreeMap();
    map.put(key, value);
    return map;
  }

  @Generates
  static <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V> generateImmutableSortedMap(
      K key, V value) {
    return ImmutableSortedMap.of(key, value);
  }

  @Generates
  static <K, V> Multimap<K, V> generateMultimap(@Nullable K key, @Nullable V value) {
    return generateListMultimap(key, value);

 * conformance of concrete {@link SortedMap} subclasses to that contract.
 *
 * @author Jared Levy
 */
// TODO: Use this class to test classes besides ImmutableSortedMap.
@GwtCompatible
public abstract class SortedMapInterfaceTest<K, V> extends MapInterfaceTest<K, V> {

  protected SortedMapInterfaceTest(
      boolean allowsNullKeys,
      boolean allowsNullValues,

 * conformance of concrete {@link SortedMap} subclasses to that contract.
 *
 * @author Jared Levy
 */
// TODO: Use this class to test classes besides ImmutableSortedMap.
@GwtCompatible
public abstract class SortedMapInterfaceTest<K, V> extends MapInterfaceTest<K, V> {

  protected SortedMapInterfaceTest(
      boolean allowsNullKeys,
      boolean allowsNullValues,

      if (window.isConnected(upperBoundWindow)) {
        return new RangesByUpperBound<>(rangesByLowerBound, window.intersection(upperBoundWindow));
      } else {
        return ImmutableSortedMap.of();
      }
    }

    @Override
    public NavigableMap<Cut<C>, Range<C>> subMap(
        Cut<C> fromKey, boolean fromInclusive, Cut<C> toKey, boolean toInclusive) {
      return subMap(

 * Collections#singletonMap(Object, Object)} and {@link java.util.LinkedHashMap} for empty,
 * singleton and regular maps respectively. For sorted maps, it's a thin wrapper around {@link
 * java.util.TreeMap}.
 *
 * @see ImmutableSortedMap
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {

      Graph<N> graph) {
    // ImmutableMap.Builder maintains the order of the elements as inserted, so the map will have
    // whatever ordering the graph's nodes do, so ImmutableSortedMap is unnecessary even if the
    // input nodes are sorted.
    ImmutableMap.Builder<N, GraphConnections<N, Presence>> nodeConnections = ImmutableMap.builder();
    for (N node : graph.nodes()) {

      ValueGraph<N, V> graph) {
    // ImmutableMap.Builder maintains the order of the elements as inserted, so the map will have
    // whatever ordering the graph's nodes do, so ImmutableSortedMap is unnecessary even if the
    // input nodes are sorted.
    ImmutableMap.Builder<N, GraphConnections<N, V>> nodeConnections = ImmutableMap.builder();
    for (N node : graph.nodes()) {

        return new ConcurrentSkipListMap<>(map);
      }
    },
    ImmutableSortedMapImpl {
      @Override
      public <K extends Comparable<K>, V> SortedMap<K, V> create(Map<K, V> map) {
        return ImmutableSortedMap.copyOf(map);
      }
    };
  }

  enum BiMapImpl implements MapsImplEnum {
    HashBiMapImpl {
      @Override
      public <K extends Comparable<K>, V> BiMap<K, V> create(Map<K, V> map) {

        return new ConcurrentSkipListMap<>(map);
      }
    },
    ImmutableSortedMapImpl {
      @Override
      public <K extends Comparable<K>, V> SortedMap<K, V> create(Map<K, V> map) {
        return ImmutableSortedMap.copyOf(map);
      }
    };
  }

  enum BiMapImpl implements MapsImplEnum {
    HashBiMapImpl {
      @Override
      public <K extends Comparable<K>, V> BiMap<K, V> create(Map<K, V> map) {