OpenXLS is the open source version of ExtenXLS -- a best-in-class Java spreadsheet SDK that allows you to read, modify and create Excel-compatible spreadsheets from your Java applications.
Supports Excel 97-2012 file formats.
- Reads and Writes Excel 97-2012 Spreadsheet Files
- High Performance, Easy to Use API
- All-Java Spreadsheet Engine
- 200+ Formulas Supported -- Accurate High Speed Calculation
- 20 Charts
- Supports PivotTables, Charts, Images, Tables, Row/Col Grouping, Sheet Hiding, Password Protection and much more!
Give a sample program for pivot operation
For a more recent build and active maintenance look at: github.com/vertex-github/openxls
very strong spreadsheet sdk does everything you need. excellent support for formulas and complex excel files.