HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short)0);
// Create a cell and put a date value in it. The first cell is not styled as a date.
HSSFCell cell = row.createCell((short)0);
// we style the second cell as a date (and time). It is important to create a new cell style from the workbook
// otherwise you can end up modifying the built in style and effecting not only this cell but other cells.
HSSFCellStyle cellStyle = wb.createCellStyle();
cell = row.createCell((short)1);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");