sheetLimit=1000 (header included), 2500 data rows
  sheet 1 "Sales": last row index 999, first data cell 1
  sheet 2 "Sales 2": last row index 999, first data cell 1000
  sheet 3 "Sales 3": last row index 502, first data cell 1999
XSSF and SXSSF files: same sheets, same formatted cell values on every 97th row

styling of a 5,000-row SXSSF file, read back with XSSF
  header cell A1 text=Order id bold=true
  freeze pane: row split at 1
  auto filter: A1:I1
  cell styles in the workbook: 5 (for 5,000 rows x 9 cells)
  B2 as Excel shows it: 30-May-2025
  amount number format: [>=10000000]##\,##\,##\,##0.00;[>=100000]##\,##\,##0.00;##,##0.00

the sheet limit
  createRow(1048575) ok
  createRow(1048576) -> IllegalArgumentException: Invalid row number (1048576) outside allowable range (0..1048575)

lakh/crore number format, rendered by POI's DataFormatter (not by Excel)
  999.50 -> 999.50
  99,999.50 -> 99,999.50
  123,456.78 -> 1,23,456.78
  1,234,567.89 -> 12,34,567.89
  12,345,678.90 -> 1,23,45,678.90
  123,456,789.10 -> 12,34,56,789.10