code: public Element tableCell(int rowNum, int colNum) {
          Element row = tableRow(rowNum);
          if (row == null || numOfTableColumns() < colNum) {
              return null;
          }
          Element thCells = row.findChild(app.newElement(Locator.TAGNAME, "th"));
          Element tdCells = row.findChild(app.newElement(Locator.TAGNAME, "td"));
          if (thCells.get().matchCount() > colNum) {
              return thCells.get(colNum);
          } else {
              return tdCells.get(colNum - thCells.get().matchCount());
          }
      }
docs: Retrieves a specific cell from the element. If the element isn't present
  or a table, or the row and cell combination doesn't exist, a null value
  will be returned.
  
  @param rowNum - the number of the row in the table - note, row numbering
  starts at 0
  @param colNum - the number of the column in the table - note, column
  numbering starts at 0
  @return WebElement: the cell element object, and all associated values
  with it