checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return floorEntry != null && floorEntry.getValue().encloses(range);
  }

  @CheckForNull
  private Range<C> rangeEnclosing(Range<C> range) {
    checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return (floorEntry != null && floorEntry.getValue().encloses(range))

    checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return floorEntry != null && floorEntry.getValue().encloses(range);
  }

  @CheckForNull
  private Range<C> rangeEnclosing(Range<C> range) {
    checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return (floorEntry != null && floorEntry.getValue().encloses(range))

  }

  @Override
  @CheckForNull
  public Entry<K, V> floorEntry(@ParametricNullness K key) {
    return delegate().floorEntry(key);
  }

  /**
   * A sensible definition of {@link #floorEntry} in terms of the {@code lastEntry()} of {@link
   * #headMap(Object, boolean)}. If you override {@code headMap}, you may wish to override {@code
   * floorEntry} to forward to this implementation.
   */
  @CheckForNull

  }

  @Override
  @CheckForNull
  public Entry<K, V> floorEntry(@ParametricNullness K key) {
    return delegate().floorEntry(key);
  }

  /**
   * A sensible definition of {@link #floorEntry} in terms of the {@code lastEntry()} of {@link
   * #headMap(Object, boolean)}. If you override {@code headMap}, you may wish to override {@code
   * floorEntry} to forward to this implementation.
   */
  @CheckForNull

    }
  }

  @Override
  @CheckForNull
  public Entry<K, V> lowerEntry(@ParametricNullness K key) {
    return headMap(key, false).lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<K, V> floorEntry(@ParametricNullness K key) {
    return headMap(key, true).lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<K, V> ceilingEntry(@ParametricNullness K key) {

  public void testFloor() {
    resetWithHole();
    assertEquals(a, navigableMap.floorEntry(a.getKey()));
    assertEquals(a.getKey(), navigableMap.floorKey(a.getKey()));
    assertEquals(a, navigableMap.floorEntry(b.getKey()));
    assertEquals(a.getKey(), navigableMap.floorKey(b.getKey()));
    assertEquals(c, navigableMap.floorEntry(c.getKey()));
    assertEquals(c.getKey(), navigableMap.floorKey(c.getKey()));
  }

  public void testFloor() {
    resetWithHole();
    assertEquals(a, navigableMap.floorEntry(a.getKey()));
    assertEquals(a.getKey(), navigableMap.floorKey(a.getKey()));
    assertEquals(a, navigableMap.floorEntry(b.getKey()));
    assertEquals(a.getKey(), navigableMap.floorKey(b.getKey()));
    assertEquals(c, navigableMap.floorEntry(c.getKey()));
    assertEquals(c.getKey(), navigableMap.floorKey(c.getKey()));
  }

    }
  }

  @Override
  @CheckForNull
  public Entry<K, V> lowerEntry(@ParametricNullness K key) {
    return headMap(key, false).lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<K, V> floorEntry(@ParametricNullness K key) {
    return headMap(key, true).lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<K, V> ceilingEntry(@ParametricNullness K key) {

      assertTrue(Thread.holdsLock(mutex));
      return delegate().firstEntry();
    }

    @Override
    public @Nullable Entry<K, V> floorEntry(K key) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().floorEntry(key);
    }

    @Override
    public @Nullable K floorKey(K key) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().floorKey(key);
    }

    return delegate.firstEntry();
  }

  @Override
  public K firstKey() {
    return delegate.firstKey();
  }

  @Override
  public @Nullable Entry<K, V> floorEntry(K key) {
    return delegate.floorEntry(checkValid(key));
  }

  @Override
  public @Nullable K floorKey(K key) {
    return delegate.floorKey(checkValid(key));
  }

  @Override
  public @Nullable V get(Object key) {