TreeBasedTable<String, Integer, Character> table = makeTable();
    populateTable(table);
    return table.rowMap().subMap("b", "x");
  }

  @Override
  protected Map<String, Map<Integer, Character>> makeEmptyMap() {
    return makeTable().rowMap().subMap("b", "x");
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "z";
  }

    table.put("b", "b", "x");
    table.put("b", "c", "y");
    table.put("b", "x", "n");
    table.put("a", "a", "d");
    table.row("b").subMap("c", "x").clear();
    assertEquals(table.row("b"), ImmutableMap.of("b", "x", "x", "n"));
    table.row("b").subMap("b", "y").clear();
    assertEquals(table.row("b"), ImmutableMap.of());
    assertFalse(table.backingMap.containsKey("b"));
  }

   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges
   * from {@code fromKey}, inclusive, to {@code toKey}, exclusive.
   *
   * <p>The {@link SortedMap#subMap} documentation states that a submap of a submap throws an {@link
   * IllegalArgumentException} if passed a {@code fromKey} less than an earlier {@code fromKey}.
   * However, this method doesn't throw an exception in that situation, but instead keeps the

    return Maps.keyOrNull(higherEntry(key));
  }

  abstract Iterator<Entry<K, V>> descendingEntryIterator();

  @Override
  public SortedMap<K, V> subMap(@ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public SortedMap<K, V> headMap(@ParametricNullness K toKey) {
    return headMap(toKey, false);
  }

  @Override

pkg syscall (freebsd-arm64), func Mknod(string, uint32, uint64) error
pkg syscall (freebsd-arm64), func Mmap(int, int64, int, int, int) ([]uint8, error)
pkg syscall (freebsd-arm64), func Munmap([]uint8) error
pkg syscall (freebsd-arm64), func Nanosleep(*Timespec, *Timespec) error
pkg syscall (freebsd-arm64), func Open(string, int, uint32) (int, error)

pkg syscall (darwin-arm64), func Mprotect([]uint8, int) error
pkg syscall (darwin-arm64), func Munlock([]uint8) error
pkg syscall (darwin-arm64), func Munlockall() error
pkg syscall (darwin-arm64), func Munmap([]uint8) error
pkg syscall (darwin-arm64), func Open(string, int, uint32) (int, error)
pkg syscall (darwin-arm64), func ParseDirent([]uint8, int, []string) (int, int, []string)

          .rowMap();
    }

    @Override
    public SortedMap<R, Map<C, V>> subMap(R fromKey, R toKey) {
      checkNotNull(fromKey);
      checkNotNull(toKey);
      return new StandardRowSortedTable<R, C, V>(sortedBackingMap().subMap(fromKey, toKey), factory)
          .rowMap();
    }

    @Override
    public SortedMap<R, Map<C, V>> tailMap(R fromKey) {

          .rowMap();
    }

    @Override
    public SortedMap<R, Map<C, V>> subMap(R fromKey, R toKey) {
      checkNotNull(fromKey);
      checkNotNull(toKey);
      return new StandardRowSortedTable<R, C, V>(sortedBackingMap().subMap(fromKey, toKey), factory)
          .rowMap();
    }

    @Override
    public SortedMap<R, Map<C, V>> tailMap(R fromKey) {

        assertEqualInOrder(
            entries.subList(i, j),
            navigableMap.subMap(entries.get(i).getKey(), entries.get(j).getKey()).entrySet());
      }
    }
  }

  @CollectionSize.Require(SEVERAL)
  public void testSubMapIllegal() {
    assertThrows(IllegalArgumentException.class, () -> navigableMap.subMap(c.getKey(), a.getKey()));
  }

  @CollectionSize.Require(absent = ZERO)

    extends AbstractImmutableSortedMapMapInterfaceTest<String, Integer> {
  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("a", 1, "b", 2, "c", 3, "d", 4, "e", 5).subMap("b", "d");
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "a";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return 4;
  }