outputStream is null, android using Http POST

Question

Im trying to upload a pdf file from my android towards my webserver

Here is my android code

public static void httpsend()
    {
        HttpURLConnection connection = null;
        DataOutputStream outputStream = null;
        DataInputStream inputStream = null;
        String pathToOurFile = Environment.getExternalStorageDirectory().toString() + "/PDF/" + samplename + ".pdf";
        String urlServer = "http://blabbla.com/cgi-bin/upload.php";
        String lineEnd = "\r\n";
        String twoHyphens = "--";
        String boundary =  "*****";

        int bytesRead, bytesAvailable, bufferSize;
        byte[] buffer;
        int maxBufferSize = 1*1024*1024;

        try
        {
            FileInputStream fileInputStream = new FileInputStream(new File(pathToOurFile) );

            URL url = new URL(urlServer);
            connection = (HttpURLConnection) url.openConnection();

            // Allow Inputs & Outputs.
            connection.setDoInput(true);
            connection.setDoOutput(true);
            connection.setUseCaches(false);

            // Set HTTP method to POST.
            connection.setRequestMethod("POST");

            connection.setRequestProperty("Connection", "Keep-Alive");
            connection.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);

            outputStream = new DataOutputStream( connection.getOutputStream() );
            outputStream.writeBytes(twoHyphens + boundary + lineEnd);
            outputStream.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + pathToOurFile +"\"" + lineEnd);
            outputStream.writeBytes(lineEnd);

            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            buffer = new byte[bufferSize];

            // Read file
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);

            while (bytesRead > 0)
            {
                outputStream.write(buffer, 0, bufferSize);
                bytesAvailable = fileInputStream.available();
                bufferSize = Math.min(bytesAvailable, maxBufferSize);
                bytesRead = fileInputStream.read(buffer, 0, bufferSize);
            }

            outputStream.writeBytes(lineEnd);
            outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

            // Responses from the server (code and message)
            int serverResponseCode = connection.getResponseCode();
            String serverResponseMessage = connection.getResponseMessage();

            fileInputStream.close();
            outputStream.flush();
            outputStream.close();
        }
        catch (Exception ex)
        {
            //Exception handling
        }
    }

now, when I debug it, the app crashes at the

outputStream = new DataOutputStream( connection.getOutputStream() );

I tried uploading via the web browser and it work, but in Android, it doesnt work.

Why is that the outputStream is null?

Thanks