Android HttpHelper class extends AsyncTask<String, String, String>

HttpHelper.java

package com.domain.myApp;

import android.os.AsyncTask;
import android.text.TextUtils;
import android.util.Log;

import org.json.JSONObject;

import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class HttpHelper extends AsyncTask<String, String, String> {

    public String UA = "Mozilla/5.0 (Linux; Android 6.0.1)";
    public int timeout = 15 * 1000;
    public String method = "GET";
    public Map<String, String> headers = new HashMap<String, String>();

    @Override
    protected String doInBackground(String... params) {

        Log.d("HttpHelper", ".doInBackground()");
        String url = params[0];

        Log.i("HttpHelper", "Loading " + url);

        try {
            HttpURLConnection conn = (HttpURLConnection) new URL(url).openConnection();

            conn.setRequestMethod(method);
            conn.addRequestProperty("User-Agent", UA);

            if (headers != null && headers.size() > 0) {
                for(String key : headers.keySet()) {
                    conn.addRequestProperty(key, headers.get(key));
                }
            }

            conn.setReadTimeout(timeout);
            conn.connect();

            JSONObject result = new JSONObject();

            // Url and StatusCode
            result.put("url", url);
            result.put("statusCode", conn.getResponseCode());

            Log.i("HttpHelper", String.format("Status %d for %s", conn.getResponseCode(), url));

            /// Extract headers
            JSONObject headers = new JSONObject();
            Map<String, List<String>> map = conn.getHeaderFields();
            if (map.size() > 0) {
                for (Map.Entry<String, List<String>> entry : map.entrySet()) {
                    String key = entry.getKey();
                    if (key != null) {
                        List<String> value = entry.getValue();
                        headers.put(key, TextUtils.join(",", value));
                    }
                }
            }
            result.put("headers", headers);

            /// Extract body
            InputStream in = new BufferedInputStream(conn.getInputStream());
            StringBuilder response = new StringBuilder();
            byte[] contents = new byte[1024];

            int bytesRead;
            while((bytesRead = in.read(contents)) != -1) {
                response.append(new String(contents, 0, bytesRead));
            }

            String body = response.toString();
            result.put("body", body);

            try {
                result.put("json", new JSONObject(body));
            } catch (Exception e) {
                Log.w("HttpHelper", "Unable to parse JSON body");
            }

            return result.toString();

        } catch (Exception e) {
            Log.e("HttpHelper", String.format("Unable to load url \"%s\". %s", url, e.getMessage()));
        }
        return null;
    }

}

Usage (from within Activity code):

String url = "http://domain.com/api/thingy/123";
HttpHelper helper = new HttpHelper() {
    @Override protected void onPostExecute(String raw) {
        try {
            JSONObject result = new JSONObject(raw);
            Log.i(TAG, result);
        } catch (Exception ex) {
            Log.e(TAG, "HttpHelper.onPostExecute() " + ex.getMessage());
        }
    }
};
helper.timeout = 5 * 1000;
helper.execute(url);