public int compareTo(Object o) {
      return toString().compareTo(o.toString());
    }

    @Override
    public String toString() {
      return "BY_TO_STRING";
    }

    private Object readResolve() {
      return INSTANCE;
    }
  }

  // Always equal is a valid total ordering. And it works for any Object.
  private static final class AlwaysEqual extends Ordering<@Nullable Object>

   * changes).
   */
  @Override
  public ImmutableMap<Object, Collection<Object>> asMap() {
    return super.asMap();
  }

  private Object readResolve() {
    return INSTANCE; // preserve singleton property
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

    private static final class SerializedForm<K> implements Serializable {
      final ImmutableMap<K, ?> map;

      SerializedForm(ImmutableMap<K, ?> map) {
        this.map = map;
      }

      Object readResolve() {
        return map.keySet();
      }

      @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
    }
  }

  @Override
  ImmutableCollection<V> createValues() {

  private static final class KeySetSerializedForm<K> implements Serializable {
    final ImmutableMap<K, ?> map;

    KeySetSerializedForm(ImmutableMap<K, ?> map) {
      this.map = map;
    }

    Object readResolve() {
      return map.keySet();
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

   * changes).
   */
  @Override
  public ImmutableMap<Object, Collection<Object>> asMap() {
    return super.asMap();
  }

  private Object readResolve() {
    return INSTANCE; // preserve singleton property
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

    @Override
    public int hashCode() {
      return System.identityHashCode(this);
    }

    @Override
    public String toString() {
      return "-\u221e";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /*

  private static final class KeySetSerializedForm<K> implements Serializable {
    final ImmutableMap<K, ?> map;

    KeySetSerializedForm(ImmutableMap<K, ?> map) {
      this.map = map;
    }

    Object readResolve() {
      return map.keySet();
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

      int i = 0;
      for (Entry<? extends Object> entry : multiset.entrySet()) {
        elements[i] = entry.getElement();
        counts[i] = entry.getCount();
        i++;
      }
    }

    Object readResolve() {
      ImmutableMultiset.Builder<Object> builder =
          new ImmutableMultiset.Builder<Object>(elements.length);
      for (int i = 0; i < elements.length; i++) {
        builder.addCopies(elements[i], counts[i]);

    final EnumSet<E> delegate;

    EnumSerializedForm(EnumSet<E> delegate) {
      this.delegate = delegate;
    }

    Object readResolve() {
      // EJ2 #76: Write readObject() methods defensively.
      return new ImmutableEnumSet<E>(delegate.clone());
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

    private final DiscreteDomain<C> domain;

    private SerializedForm(DiscreteDomain<C> domain) {
      this.domain = domain;
    }

    private Object readResolve() {
      return new EmptyContiguousSet<>(domain);
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  @GwtIncompatible
  @J2ktIncompatible