android - how to make a method in asynctask

Kindly guide me how to make all this into an asynctask method. I have to make this code in asynctask because it is giving a null value because of calling it in uithread. Kindly show me the correct way how to make this possible. I have seen many, many questions on stackoverflow but I am unable to make this work.

I have seen following questions:

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android.os.NetworkOnMainThreadException with android 4.2

NetworkOnMainThreadException

android.os.NetworkOnMainThreadException

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My class is:

public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

public JSONParser() {
}
public JSONObject makeHttpRequest(String url, String method, List params)
{  try
{
if(method == "POST")
{
    DefaultHttpClient httpClient = new DefaultHttpClient();
    HttpPost httpPost = new HttpPost(url);
    httpPost.setEntity(new UrlEncodedFormEntity(params));

    HttpResponse httpResponse = httpClient.execute(httpPost);
    HttpEntity httpEntity = httpResponse.getEntity();
    is = httpEntity.getContent();
}
else if(method == "GET"){
 DefaultHttpClient httpClient = new DefaultHttpClient();
    String paramString = URLEncodedUtils.format(params, "utf-8"); url += "?" + paramString;
    HttpGet httpGet = new HttpGet(url);
    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 {
         jObj = new JSONObject(json);
     }
     catch (JSONException e) {
         Log.e("JSON Parser", "Error parsing data " + e.toString());
     }
return jObj;
}

}