Getting null pointer exception when try to write data second time in loop using selenium

Question

I am writing to data in excel , My process is :

Get data from website
Store data into Array
Write into excel

Problem :

It writes data first time perfectly , But second time when it reaches to Write() function , it fires null pointer exception. I have checked by debug that data is in array but not writing second time.

Code :

public static void Write_To_Excel() throws IOException
    {


        int lastrow = 0;
        FileInputStream input = new FileInputStream("E:\\Data.xls");
        Workbook wb = new HSSFWorkbook(input);
        Sheet sh = wb.getSheet("sheet1");
        Row row = sh.getRow(0);
        lastrow = sh.getLastRowNum();



        for(int c=0;c<URLs.size();c++)
        {

            System.out.println(URLs.get(c).toString());
            //driver.findElement(By.cssSelector("body")).sendKeys(Keys.CONTROL +"\t");
            driver.get(URLs.get(c).toString());

                 String Name = driver.findElement(By.id("ProductOverrideName")).getAttribute("value");
                 String Manufacturer = driver.findElement(By.id("ManufacturerName")).getAttribute("value");
                 String MPN = driver.findElement(By.id("ProductManufacturerPartNumber")).getAttribute("value");
                 String Size = driver.findElement(By.id("SizeName")).getAttribute("value");
                 String Color = driver.findElement(By.id("ColorName")).getAttribute("value");
                 String Option = driver.findElement(By.id("OptionName")).getAttribute("value");
                 String Mkeywords = driver.findElement(By.id("ProductOverrideMetaKeywords")).getAttribute("value");
                 String Mdesc = driver.findElement(By.id("ProductOverrideMetaDescription")).getAttribute("value");

                 driver.switchTo().frame(0);

                 String Desc = driver.findElement(By.xpath("/html/body")).getText();
                 driver.switchTo().defaultContent();

                 ProductData = new ArrayList<String>();

                 ProductData.add(Name);
                 ProductData.add(Manufacturer);
                 ProductData.add(MPN);
                 ProductData.add(Size);
                 ProductData.add(Color);
                 ProductData.add(Option);
                 ProductData.add(Mkeywords);
                 ProductData.add(Mdesc);
                 ProductData.add(Desc);

                 lastrow = sh.getLastRowNum();
                 Row newrow = sh.getRow(lastrow);
                 newrow = sh.createRow(lastrow+1); 


                 for(int d=0;d<ProductData.size();d++)
                 {
                     try{

                     System.out.println(ProductData.get(d).toString());
                     Cell cell = newrow.createCell(d);
                     cell.setCellValue(ProductData.get(d).toString());


                 }catch(Exception E)
                 {

                     E.printStackTrace();
                 }

                 }

                 input.close();

                 try{
                  FileOutputStream webdata = new FileOutputStream ("E:\\Data.xls");
                  wb.write(webdata);
                  wb.close();


                 }catch(Exception E)

                 {

                     E.printStackTrace();

                 }
             }

        }

First time everything works fine , When it comes second time at wb.write(webdata); , It fires null pointer exception.

Try closing it after the loop. Since now you close wb and try to write later again. — ctst, Jan 21 '16 at 17:10
Can we get a stacktrace? 'wb' is a `HSSFWorkbook`, 'webdata' is a `FileOutputStream`, so Selenium / WebDriver are probably unrelated to this issue. — Andrew Regan, Jan 21 '16 at 17:10
@AndrewRegan - Yes I know that this is not selenium related issue , I just mentioned because I am using it with selenium so. — Helping Hands, Jan 21 '16 at 17:12
When you close the wb object, the pointer becomes null. You need to reopen it again. — Rabbit Guy, Jan 21 '16 at 17:13
No it doesn't, wb will never be non-null. Presumably the error is within the bowels of POI, which is why we need the stacktrace. Note that `WebElement.getAttribute(...)` can return null, so that may be the cause, i.e. the ProductData `ArrayList` may contain null elements. — Andrew Regan, Jan 21 '16 at 17:14
@ctst - When I am closing it after loop , it is working fine. But what is reason that it is sending null pointer when I close it within loop? — Helping Hands, Jan 21 '16 at 17:20
You will get a null pointer exception when you try to write to a stream that is closed. — Rabbit Guy, Jan 21 '16 at 17:42

Getting null pointer exception when try to write data second time in loop using selenium

0 Answers0