remove data validation of HSSF sheet using Apache POI

Question

How to remove the data validation of excel from using apache POI. I have following code. On first run, the dropdowns are getting created properly, but the same is not getting updated once I run the program again with different values in the String List.

FileInputStream fsIP= new FileInputStream(new File("D:\\template3.xls")); //Read the spreadsheet that needs to be updated              
                HSSFWorkbook wb = new HSSFWorkbook(fsIP); //Access the workbook           
                HSSFSheet worksheet = wb.getSheetAt(0); //Access the worksheet, so that we can update / modify it.
          //     System.out.println(worksheet.getRow(1).getCell(2));
                Cell cell = null; // declare a Cell object                
                DataValidation dataValidation = null;
                DataValidationConstraint constraint = null;
                DataValidationHelper validationHelper = null;
                CellRangeAddressList addressList = new  CellRangeAddressList(0,5,0,5);

                //cell = worksheet.getRow(2).getCell(2);   // Access the second cell in second row to update the value 
                DVConstraint dvConstraint = DVConstraint.createExplicitListConstraint(new String[]{"124", "20", "30"});
                  dataValidation = new HSSFDataValidation(addressList, dvConstraint);
                  dataValidation.setSuppressDropDownArrow(false);

                  worksheet.addValidationData(dataValidation);
               // cell.setCellValue("OverRide Last Name");  // Get current cell value value and overwrite the value

                fsIP.close(); //Close the InputStream

                FileOutputStream output_file =new FileOutputStream(new File("D:\\template3.xls"));  //Open FileOutputStream to write updates
                wb.write(output_file); //write changes

               output_file.close();  //close the stream   

Answer 1

I had to remove/edit DataValidation inside sheet and couldn't find answer anywhere, here is what I did. (using apache-poi:3.14)

First, you shouldn't use this method except for reading concerns :

worksheet.getSheet("MySheet").getDataValidations()

It is always sending copies of DataValidation so that editing them will do nothing.

I had to go with this :

worksheet.getSheet("MySheet").getCTWorksheet().getDataValidations().getDataValidationList()

Then you will be able to edit or remove DataValidation from here using get/set/remove methods.

Regards.