Android : Java Android How to organize notification service

I'm noob in java and just started teaching. I want to organize service that connects to server and gets jsonObject from there. I also have class in my application that do the same thing. So can I connect from service to that class or I need to write new code separately in service?

Now I tried to do it in service, but there are some problems with JSON.

Here is my service:

public class NoticeService extends IntentService {
    NotificationManager nm;
    SharedPreferences sPref;

    public NoticeService() {
        super("appNotices");
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);

    }

    @Override
    public void onCreate() {
        super.onCreate();
        nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        Context context = getApplicationContext();
        sPref = PreferenceManager.getDefaultSharedPreferences(context);
        sPref = context.getSharedPreferences("token", MODE_PRIVATE);
    }

    public int onStartCommand(Intent intent, int flags, int startId) {
        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        sendNotif();
        stopSelf();
        return START_STICKY;
    }

    void sendNotif() throws JSONException{

        JSONObject res = checkNotices();

        //here I'll send notices..
    }

    private JSONObject checkNotices() throws JSONException{
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://example.com/api");
        JSONObject res = null;

        // Create a new HttpClient and Post Header
        JSONObject json = new JSONObject();
        JSONObject cont = new JSONObject();


        cont.put("action", "/user/get_notices");
        cont.put("token", sPref.getString("token",""));
        json.put("request", cont);

        Log.d("Requesting","json: " + json.toString());
        Log.d("Requesting","Ran send");
        try{
            StringEntity se = new StringEntity(json.toString());
            httppost.setEntity(se);
            httppost.setHeader("Accept", "application/json");
            httppost.setHeader("Content-type", "application/json");
            HttpResponse httpResponse = httpclient.execute(httppost);
            Log.d("Requesting",httpResponse.toString());
            // Execute HTTP Post Request
            System.out.print(json);
            HttpResponse response = httpclient.execute(httppost);

            // for JSON:
            if(response != null)
            {
                InputStream is = response.getEntity().getContent();

                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                StringBuilder sb = new StringBuilder();

                String line = null;
                try {
                    while ((line = reader.readLine()) != null) {
                        sb.append(line + "\n");
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                String d = sb.toString();
                Log.d("Requesting log",d);
                JSONObject jObj = new JSONObject(d);
                JSONObject resObj = jObj.getJSONObject("response");
                res = resObj.getJSONObject("data");

            }

        }catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }
        return res;
    }

    @Override
    public void onDestroy() {
        // I want to restart this service again in one hour
        AlarmManager alarm = (AlarmManager)getSystemService(ALARM_SERVICE);
        alarm.set(
                alarm.RTC_WAKEUP,
                System.currentTimeMillis() + (1000 * 20 * 1),
                PendingIntent.getService(this, 0, new Intent(this, NoticeService.class), 0)
        );
    }

    public IBinder onBind(Intent arg0) {
        return null;
    }
}

So now android studio asks me to add "throws exception" to onStartCommand() but then I have error in log: Impossiblу to throws exceptions in onStartCommand().

What I have to do?