@Override
  protected SortedMap<String, Integer> makeEmptyMap() {
    return new SimpleForwardingSortedMap<>(
        new TreeMap<String, Integer>(Ordering.<String>natural().nullsFirst()));
  }

  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    final SortedMap<String, Integer> sortedMap = makeEmptyMap();
    sortedMap.put("one", 1);
    sortedMap.put("two", 2);
    sortedMap.put("three", 3);

   * returns a {@link SortedMap}, instead of the {@link Map} specified in the {@link Table}
   * interface.
   *
   * @since 10.0 (<a href="https://github.com/google/guava/wiki/Compatibility" >mostly
   *     source-compatible</a> since 7.0)
   */
  @Override
  public SortedMap<C, V> row(R rowKey) {
    return new TreeRow(rowKey);
  }

  private class TreeRow extends Row implements SortedMap<C, V> {

  @Override
  protected SortedMap<String, Integer> makeEmptyMap() {
    return new SimpleForwardingSortedMap<>(
        new TreeMap<String, Integer>(Ordering.<String>natural().nullsFirst()));
  }

  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    final SortedMap<String, Integer> sortedMap = makeEmptyMap();
    sortedMap.put("one", 1);
    sortedMap.put("two", 2);
    sortedMap.put("three", 3);

import com.google.common.annotations.GwtCompatible;
import java.util.SortedMap;

@GwtCompatible
@ElementTypesAreNonnullByDefault
public class FilteredSortedMapTest extends AbstractFilteredMapTest {
  @Override
  SortedMap<String, Integer> createUnfiltered() {
    return Maps.newTreeMap();
  }

  public void testFirstAndLastKeyFilteredMap() {
    SortedMap<String, Integer> unfiltered = createUnfiltered();

    return SortedMapTestSuiteBuilder.using(
            new TestStringSortedMapGenerator() {
              @Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                SortedMap<String, String> map = populate(new TreeMap<String, String>(), entries);
                return Collections.checkedSortedMap(map, String.class, String.class);
              }

    return SortedMapTestSuiteBuilder.using(
            new TestStringSortedMapGenerator() {
              @Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                SortedMap<String, String> map = populate(new TreeMap<String, String>(), entries);
                return Collections.checkedSortedMap(map, String.class, String.class);
              }

    suite.addTest(
        SortedMapTestSuiteBuilder.using(
                new TestStringSortedMapGenerator() {
                  @Override
                  protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                    SortedMap<String, String> map = new NonNavigableSortedMap();
                    putEntries(map, entries);
                    map.putAll(ENTRIES_TO_FILTER);

    suite.addTest(
        SortedMapTestSuiteBuilder.using(
                new TestStringSortedMapGenerator() {
                  @Override
                  protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                    SortedMap<String, String> map = new NonNavigableSortedMap();
                    putEntries(map, entries);
                    map.putAll(ENTRIES_TO_FILTER);

import com.google.common.annotations.GwtCompatible;
import java.util.SortedMap;

@GwtCompatible
@ElementTypesAreNonnullByDefault
public class FilteredSortedMapTest extends AbstractFilteredMapTest {
  @Override
  SortedMap<String, Integer> createUnfiltered() {
    return Maps.newTreeMap();
  }

  public void testFirstAndLastKeyFilteredMap() {
    SortedMap<String, Integer> unfiltered = createUnfiltered();

    return orderEntriesByKey(insertionOrder);
  }

  @Override
  protected abstract SortedMap<String, String> create(Entry<String, String>[] entries);

  @Override
  public SortedMap<String, String> create(Object... entries) {
    return (SortedMap<String, String>) super.create(entries);
  }