HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short) 1);
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("This is a test of merging");
sheet.addMergedRegion(new Region(1,(short)1,1,(short)2));
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();