how to solve getContentResolver().getType null?

Question

I am trying to execute following like following

Uri.parse(pictureImagePath) is /storage/emulated/0/Pictures/20171125_131914.jpg

But it is returning null. Am i missing something?? Please help!!!

Following is calling the camera:

if(Build.VERSION.SDK_INT>=24){
            try{
                Method m = StrictMode.class.getMethod("disableDeathOnFileUriExposure");
                m.invoke(null);
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String imageFileName = timeStamp + ".jpg";
        File storageDir = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        pictureImagePath = storageDir.getAbsolutePath() + "/" + imageFileName;
        File file = new File(pictureImagePath);
        Uri outputFileUri = Uri.fromFile(file);
        Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
        startActivityForResult(cameraIntent, REQUEST_CAMERA);

following is the code

                File imgFile = new File(pictureImagePath);
                if (imgFile.exists()){


                    bitmapImage = null;
                    bitmapImage = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
                    RequestBody requestFile = RequestBody.create(MediaType.parse(getContentResolver().getType(Uri.fromFile(imgFile))), imgFile);