public static class Chars extends SampleElements<Character> {
    public Chars() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super('b', 'a', 'c', 'd', 'e');
    }
  }

  public static class Enums extends SampleElements<AnEnum> {
    public Enums() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super(AnEnum.B, AnEnum.A, AnEnum.C, AnEnum.D, AnEnum.E);
    }

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Basic implementation of the {@link SortedSetMultimap} interface. It's a wrapper around {@link
 * AbstractMapBasedMultimap} that converts the returned collections into sorted sets. The {@link
 * #createCollection} method must return a {@code SortedSet}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Basic implementation of the {@link SortedSetMultimap} interface. It's a wrapper around {@link
 * AbstractMapBasedMultimap} that converts the returned collections into sorted sets. The {@link
 * #createCollection} method must return a {@code SortedSet}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

import java.util.Comparator;
import java.util.SortedSet;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A sorted set multimap which forwards all its method calls to another sorted set multimap.
 * Subclasses should override one or more methods to modify the behavior of the backing multimap as

import java.util.SortedSet;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A sorted set which forwards all its method calls to another sorted set. Subclasses should
 * override one or more methods to modify the behavior of the backing sorted set as desired per the
 * <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An immutable sorted set with one or more elements. TODO(jlevy): Consider separate class for a
 * single-element sorted set.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings({"serial", "rawtypes"})

@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class TreeMultiset<E extends @Nullable Object> extends AbstractSortedMultiset<E>
    implements Serializable {

  /**
   * Creates a new, empty multiset, sorted according to the elements' natural order. All elements
   * inserted into the multiset must implement the {@code Comparable} interface. Furthermore, all

 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
final class RegularImmutableSortedSet<E> extends ImmutableSortedSet<E> {

  /** true if this set is a subset of another immutable sorted set. */
  final boolean isSubset;

  private @Nullable Comparator<E> unusedComparatorForSerialization;
  private @Nullable E unusedElementForSerialization;

and, as there seemed to be no sort of chance of her ever getting
out of the room again, no wonder she felt unhappy.

  `It was much pleasanter at home,' thought poor Alice, `when one
wasn't always growing larger and smaller, and being ordered about
by mice and rabbits.  I almost wish I hadn't gone down that
rabbit-hole--and yet--and yet--it's rather curious, you know,
this sort of life!  I do wonder what CAN have happened to me!

import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Basic implementation of a {@link SortedSetMultimap} with a sorted key set.
 *
 * <p>This superclass allows {@code TreeMultimap} to override methods to return navigable set and
 * map types in non-GWT only, while GWT code will inherit the SortedMap/SortedSet overrides.
 *