I am developing an app that downloads an XML file, parses it and then displays the information on the screen. I get a `NullPointerException` Exception error in the following code:

here is the code:

```
private class DownloadXmlTask extends AsyncTask<String, Void, List<vehicleInfo>> {
    @Override
    protected List<vehicleInfo> doInBackground(String... url) {
        try {
            return getvehicles.processBusTime();
        } catch (IOException e) {
           return null;
        } catch (XmlPullParserException e) {
            return null;
        }
    }

    @Override
    protected void onPostExecute(List<vehicleInfo> result) {

            for (int record = 0; record < result.size(); record++) {

            double latitude = result.get(record).latitude;
            double longitude = result.get(record).longitude;

                mMap.addMarker(new MarkerOptions().position(new LatLng(latitude,     longitude)).title("Marker"));

        }

    }
}

```

it is returns a `NullPointerException` at the line: `for (int record = 0; record < result.size(); record++) {`

what could be the issue?

thanks.