title: NullPointerException when try to write result to excel
body: <p>Can someone help with this code?<br>
  I receive an error message about NullPointerException at 41 row. I know that it returns null but this value is required for following verification. The general task is to write result to excel file.</p>
  
  <pre><code> public class ExcelUtils {
  
          public static void main(String[] args)
          {
              //Blank workbook
              XSSFWorkbook workbook = new XSSFWorkbook();
  
              //Create a blank sheet
              XSSFSheet sheet = workbook.createSheet("Employee Data");
  
              String Result = "TEST TEST TEST";
              int RowNum = 2;
              int ColNum = 3;
              XSSFSheet ExcelWSheet = sheet;
              XSSFCell Cell;
              XSSFRow Row;
  
              try
                  {
  
  
                      Row  = ExcelWSheet.getRow(RowNum);
  
                      Cell = Row.getCell(ColNum, org.apache.poi.ss.usermodel.Row.RETURN_BLANK_AS_NULL);
  
                      if (Cell == null) {
  
                          Cell = Row.createCell(ColNum);
  
                          Cell.setCellValue(Result);
  
                          } else {
  
                              Cell.setCellValue(Result);
  
                          }
  
  
  
  
                  //---------------------------------------------------
  
  
                      //try
                     // {
                      //Write the workbook in file system
                      FileOutputStream out = new FileOutputStream(new File("howtodoinjava_demo.xlsx"));
                      workbook.write(out);
                      out.close();
                      System.out.println("howtodoinjava_demo.xlsx written successfully on disk.");
                  }
                  catch (Exception e)
                  {
                      e.printStackTrace();
                  }
  
          }
  
  
      }
  </code></pre>