// Create a new workbook Workbook workbook = new Workbook(); // Open an excel file InputStream fileStream = this.getResourceStream("xlsx/Medical office start-up expenses 1.xlsx"); workbook.open(fileStream); //Use a password to protect all the worksheet. If you forget the password, you cannot unprotect the worksheet. for (IWorksheet worksheet : workbook.getWorksheets()) { worksheet.protect("Y6dh!et5"); } // Save to an excel file workbook.save("ProtectWorksheetWithPassword.xlsx");