code: private void writeRow(String... columns) throws IOException {
          StringBuilder html = new StringBuilder();
          html.append("<tr>");
          for(String data : columns) {
              html.append("<td>").append(data).append("</td>");
          }
          html.append("</tr>\n");
          writer.write(html.toString());
      }
docs: Write data to file
  @param columns column data
  @throws IOException exception