Android : JSON Parser with async task (GET and POST methods)

public class BackGroundTask extends AsyncTask<String, String, JSONObject>{
    List<NameValuePair> postparams= new ArrayList<NameValuePair>();
    String URL=null;
    String method = null;
public BackGroundTask(String url, String method, List<NameValuePair> params) {
        URL=url;
        postparams=params;
        this.method = method;
    }
    @Override
    protected JSONObject doInBackground(String... params) {
        // TODO Auto-generated method stub
        // Making HTTP request
        try {
    // Making HTTP request 
        // check for request method

    if(method.equals("POST")){
            // request method is POST
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(postparams)); 

     //ADDED BY ME FOR AUTHENTICATION
	    String encoded_login = Base64.encodeToString(unp.getBytes(), Base64.NO_WRAP);
	    httpPost.setHeader(new BasicHeader("Authorization", "Basic "+encoded_login));           

 HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            // request method is GET
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(postparams, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url); 

  //ADDED BY ME FOR AUTHENTICATION
	    String encoded_login = Base64.encodeToString(unp.getBytes(), Base64.NO_WRAP);
	    httpPost.setHeader(new BasicHeader("Authorization", "Basic "+encoded_login));           

 HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
        }           

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {

        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

   }
 }
}

Note : the green color codes are being used for authentication in the server folder

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