} catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().retainAll(null) doesn't throws NPE.
    }
  }

  @Override

    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().retainAll(null) doesn't throws NPE.
    }
  }

  @Override

  @Override
  protected Table<String, Integer, Character> create(@Nullable Object... data) {
    Supplier<TreeMap<Integer, Character>> factory =
        new Supplier<TreeMap<Integer, Character>>() {
          @Override
          public TreeMap<Integer, Character> get() {
            return Maps.newTreeMap();
          }
        };

    }

    /**
     * {@link TreeMap}の新しいインスタンスを作成して返します。
     *
     * @param <K>
     *            {@link TreeMap}のキーの型
     * @param <V>
     *            {@link TreeMap}の値の型
     * @return {@link TreeMap}の新しいインスタンス
     * @see TreeMap#TreeMap()
     */
    public static <K, V> TreeMap<K, V> newTreeMap() {
        return new TreeMap<>();
    }

    /**

  @Override
  protected Table<String, Integer, Character> create(@Nullable Object... data) {
    Supplier<TreeMap<Integer, Character>> factory =
        new Supplier<TreeMap<Integer, Character>>() {
          @Override
          public TreeMap<Integer, Character> get() {
            return Maps.newTreeMap();
          }
        };

  private static class Factory<C, V> implements Supplier<TreeMap<C, V>>, Serializable {
    final Comparator<? super C> comparator;

    Factory(Comparator<? super C> comparator) {
      this.comparator = comparator;
    }

    @Override
    public TreeMap<C, V> get() {
      return new TreeMap<>(comparator);
    }

    private static final long serialVersionUID = 0;
  }

  /**

    }

    /**
     * 指定されたキーと値を持つ{@link TreeMap}を構築するための{@literal Maps}を返します。
     *
     * @param <KEY>
     *            <code>Map</code>のキーの型
     * @param <VALUE>
     *            <code>Map</code>の値ーの型
     * @param key
     *            <code>Map</code>に追加されるキー
     * @param value
     *            <code>Map</code>に追加される値
     * @return 指定されたキーと値を持つ{@link TreeMap}を構築するための{@literal Maps}
     */

import static com.google.common.graph.GraphConstants.DEFAULT_NODE_COUNT;
import static com.google.common.graph.Graphs.checkNonNegative;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import javax.annotation.CheckForNull;

/**
 * Standard implementation of {@link ValueGraph} that supports the options supplied by {@link
 * AbstractGraphBuilder}.
 *

  ImmutableSortedSet<K> createKeySet() {
    // the keySet() of the delegate is only a Set and TreeMap.navigatableKeySet
    // is not available in GWT yet.  To keep the code simple and code size more,
    // we make a copy here, instead of creating a view of it.
    //
    // TODO: revisit if it's unbearably slow or when GWT supports
    // TreeMap.navigatbleKeySet().
    return ImmutableSortedSet.copyOf(comparator, sortedDelegate.keySet());
  }

public class SortedIterablesTest extends TestCase {
  public void testSameComparator() {
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    // Before JDK6 (including under GWT), the TreeMap keySet is a plain Set.
    if (Maps.newTreeMap().keySet() instanceof SortedSet) {
      assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    }
    assertTrue(