android - stackoverflow error using gson -

i trying places of interest , enabled apis "google maps android api & google places api". when post url in web browser api_key.

error message:
" ip, site or mobile application not authorized use api key. request received ip address 212.241.70.124, empty referer".

2nd thing when run code error: " java.lang.stackoverflowerror: stack size 1036kb gson". kindly let me know doing wrong? thankful you!

java code:

   public class foodfragment extends fragment {  private supportmapfragment mapfragment;  @nullable @override public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {      view view= inflater.inflate(r.layout.food_layout, null);      // getting map here , it's okay.      googlemap();      postfetcher postfetcher=new postfetcher();     postfetcher.execute();      return view;     }         private class postfetcher extends asynctask<void,void,string>{      private static final string tag = "postfetcher";     public static final string server_url = " https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=-33.8670522,151.1957362&radius=50&type=restaurant&name=cruise&key=my api key here";       @override     protected string doinbackground(void... params) {          try {              gson gson = new gsonbuilder().create();             foodfragment jsondata = gson.fromjson(server_url, foodfragment.class);              system.out.println("data="+jsondata);          } catch (exception ex) {             log.e(tag, "failed parse json due to: " + ex);         }         return null;     }   }  } 

foodfragment jsondata = gson.fromjson(server_url, foodfragment.class); 

foodfragment.class name of current class file, not java object json represents. second parameter must pojo , first, json string, not url.

it seem need make http request first, may

mapdata map = gson.fromjson(serverresponse, mapdata.class); 

after create mapdata class, of course.