connecting to an HTTP server and sending a POST request

doInBackground.java

HttpURLConnection urlConnection = null;
StringBuffer response = new StringBuffer();
try {
    URL url = new URL(params[0]);
    urlConnection = (HttpURLConnection) url.openConnection();
    urlConnection.setRequestProperty("User-Agent", "Mozilla/5.0");
    urlConnection.setDoInput(true);
    urlConnection.setDoOutput(true);
    urlConnection.setRequestProperty("Content-Type", "application/json");
    urlConnection.setRequestMethod("POST");
    urlConnection.setConnectTimeout(5000);

    // Send the post body
    DataOutputStream wr = new DataOutputStream (urlConnection.getOutputStream());
    wr.writeBytes(postData.toString());
    wr.flush ();
    wr.close ();

    if (urlConnection.getResponseCode() ==  HttpURLConnection.HTTP_OK) {
        //Get Response
        InputStream is = urlConnection.getInputStream();
        BufferedReader rd = new BufferedReader(new InputStreamReader(is));
        String line;

        while((line = rd.readLine()) != null) {
            response.append(line);
            response.append('\n');
        }
        rd.close();
    } else {
        response.append("HTTP Response code not OK - " + urlConnection.getResponseCode());
    }
} catch (IOException e) {
    e.printStackTrace();
} finally {
    if (urlConnection != null) {
        urlConnection.disconnect();
    }
}
return response.toString();