return (Table<String, String, Integer>) table;
            });
    Cell<String, String, @Nullable Integer> cell = immutableCell("one", "uno", null);
    assertThrows(
        NullPointerException.class,
        () -> Stream.of((Cell<String, String, Integer>) cell).collect(collector));
  }

  public void testToTableConflict() {
    Collector<Cell<String, String, Integer>, ?, Table<String, String, Integer>> collector =

    for (Table.Cell<? extends R, ? extends C, ? extends V> cell : table.cellSet()) {
      put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
    }
  }

  @LazyInit private transient @Nullable Set<Cell<R, C, V>> cellSet;

  @Override
  public Set<Cell<R, C, V>> cellSet() {
    Set<Cell<R, C, V>> result = cellSet;

        checkNotNull(cell.getRowKey(), "row");
        checkNotNull(cell.getColumnKey(), "column");
        checkNotNull(cell.getValue(), "value");
        @SuppressWarnings("unchecked") // all supported methods are covariant
        Cell<R, C, V> immutableCell = (Cell<R, C, V>) cell;
        cells.add(immutableCell);
      } else {
        put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
      }

        checkNotNull(cell.getRowKey(), "row");
        checkNotNull(cell.getColumnKey(), "column");
        checkNotNull(cell.getValue(), "value");
        @SuppressWarnings("unchecked") // all supported methods are covariant
        Cell<R, C, V> immutableCell = (Cell<R, C, V>) cell;
        cells.add(immutableCell);
      } else {
        put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
      }

    for (int i = 0; i < cellList.size(); i++) {
      Cell<R, C, V> cell = cellList.get(i);
      R rowKey = cell.getRowKey();
      C columnKey = cell.getColumnKey();
      V value = cell.getValue();

      /*
       * These requireNonNull calls are safe because we construct the maps to hold all the provided
       * cells.
       */
      cellRowIndices[i] = requireNonNull(rowIndex.get(rowKey));

      return Maps.transformValues(fromTable.column(columnKey), function);
    }

    Cell<R, C, V2> applyToValue(Cell<R, C, V1> cell) {
      return immutableCell(cell.getRowKey(), cell.getColumnKey(), function.apply(cell.getValue()));
    }

    @Override
    Iterator<Cell<R, C, V2>> cellIterator() {
      return Iterators.transform(fromTable.cellSet().iterator(), this::applyToValue);
    }

    }

    @Override
    public Set<Cell<String, Integer, Character>> create(Object... elements) {
      Table<String, Integer, Character> table = createTable();
      for (Object element : elements) {
        @SuppressWarnings("unchecked")
        Cell<String, Integer, Character> cell = (Cell<String, Integer, Character>) element;
        table.put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
      }

    for (Table.Cell<? extends R, ? extends C, ? extends V> cell : table.cellSet()) {
      put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
    }
  }

  @LazyInit private transient @Nullable Set<Cell<R, C, V>> cellSet;

  @Override
  public Set<Cell<R, C, V>> cellSet() {
    Set<Cell<R, C, V>> result = cellSet;

  public void testImmutableEntrySerialization() {
    Cell<String, Integer, Character> entry = immutableCell("foo", 1, 'a');
    SerializableTester.reserializeAndAssert(entry);
  }

  public void testImmutableEntryToString() {
    Cell<String, Integer, Character> entry = immutableCell("foo", 1, 'a');
    assertEquals("(foo,1)=a", entry.toString());

    Cell<@Nullable String, @Nullable Integer, @Nullable Character> nullEntry =

    this.singleRowKey = checkNotNull(rowKey);
    this.singleColumnKey = checkNotNull(columnKey);
    this.singleValue = checkNotNull(value);
  }

  SingletonImmutableTable(Cell<R, C, V> cell) {
    this(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
  }

  @Override
  public ImmutableMap<R, V> column(C columnKey) {
    checkNotNull(columnKey);
    return containsColumn(columnKey)