protected SortedMap<String, Integer> makePopulatedMap() {
    NavigableMap<String, Integer> map = new SafeTreeMap<>();
    map.put("one", 1);
    map.put("two", 2);
    map.put("three", 3);
    return SerializableTester.reserialize(map);
  }

  @Override
  protected SortedMap<String, Integer> makeEmptyMap() throws UnsupportedOperationException {
    NavigableMap<String, Integer> map = new SafeTreeMap<>();

@GwtIncompatible
public final class SafeTreeMap<K, V> implements Serializable, NavigableMap<K, V> {
  @SuppressWarnings("unchecked")
  private static final Comparator<Object> NATURAL_ORDER =
      new Comparator<Object>() {
        @Override
        public int compare(Object o1, Object o2) {
          return ((Comparable<Object>) o1).compareTo(o2);
        }
      };

  private final NavigableMap<K, V> delegate;

  public SafeTreeMap() {

  }

  <K, V> void testNavigationAgainstExpected(
      NavigableMap<K, V> expected, NavigableMap<K, V> navigableMap, Iterable<K> keysToTest) {
    for (K key : keysToTest) {
      assertEquals(expected.lowerEntry(key), navigableMap.lowerEntry(key));
      assertEquals(expected.floorEntry(key), navigableMap.floorEntry(key));
      assertEquals(expected.ceilingEntry(key), navigableMap.ceilingEntry(key));

import java.util.Iterator;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.SortedMap;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Skeletal implementation of {@link NavigableMap}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible

        TestSortedMapGenerator<K, V> delegate, Bound to, Bound from) {
      super(delegate, to, from);
    }

    @Override
    NavigableMap<K, V> createSubMap(SortedMap<K, V> sortedMap, K firstExclusive, K lastExclusive) {
      NavigableMap<K, V> map = (NavigableMap<K, V>) sortedMap;
      if (from == Bound.NO_BOUND && to == Bound.INCLUSIVE) {
        return map.headMap(lastInclusive, true);

  protected SortedMap<String, Integer> makePopulatedMap() {
    NavigableMap<String, Integer> map = new SafeTreeMap<>();
    map.put("one", 1);
    map.put("two", 2);
    map.put("three", 3);
    return SerializableTester.reserialize(map);
  }

  @Override
  protected SortedMap<String, Integer> makeEmptyMap() throws UnsupportedOperationException {
    NavigableMap<String, Integer> map = new SafeTreeMap<>();

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

 * @author Louis Wasserman
 * @since 14.0
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@GwtIncompatible // NavigableMap
@ElementTypesAreNonnullByDefault
public final class TreeRangeMap<K extends Comparable, V> implements RangeMap<K, V> {

  private final NavigableMap<Cut<K>, RangeMapEntry<K, V>> entriesByLowerBound;

  public static <K extends Comparable, V> TreeRangeMap<K, V> create() {

  }

  @GwtIncompatible // NavigableMap
  static <K extends @Nullable Object, V extends @Nullable Object> NavigableMap<K, V> navigableMap(
      NavigableMap<K, V> navigableMap) {
    return navigableMap(navigableMap, null);
  }

  @GwtIncompatible // NavigableMap
  static <K extends @Nullable Object, V extends @Nullable Object> NavigableMap<K, V> navigableMap(

  }

  @GwtIncompatible // NavigableMap
  static <K extends @Nullable Object, V extends @Nullable Object> NavigableMap<K, V> navigableMap(
      NavigableMap<K, V> navigableMap) {
    return navigableMap(navigableMap, null);
  }

  @GwtIncompatible // NavigableMap
  static <K extends @Nullable Object, V extends @Nullable Object> NavigableMap<K, V> navigableMap(