Background location service. It will be restarted even after killing the app.
MainActivity.java
public class MainActivity extends AppCompatActivity {
    AlarmManager alarmManager;
    Button stop;
    PendingIntent pendingIntent;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (alarmManager == null) {
            alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
            Intent intent = new Intent(this, AlarmReceive.class);
            pendingIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
            alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 30000,
                    pendingIntent);
        }
    }
}
BookingTrackingService.java
public class BookingTrackingService extends Service implements LocationListener {
    private static final String TAG = "BookingTrackingService";
    private Context context;
    boolean isGPSEnable = false;
    boolean isNetworkEnable = false;
    double latitude, longitude;
    LocationManager locationManager;
    Location location;
    private Handler mHandler = new Handler();
    private Timer mTimer = null;
    long notify_interval = 30000;
    public double track_lat = 0.0;
    public double track_lng = 0.0;
    public static String str_receiver = "servicetutorial.service.receiver";
    Intent intent;
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
    @Override
    public void onCreate() {
        super.onCreate();
        mTimer = new Timer();
        mTimer.schedule(new TimerTaskToGetLocation(), 5, notify_interval);
        intent = new Intent(str_receiver);
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        this.context = this;
        return START_NOT_STICKY;
    }
    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.e(TAG, "onDestroy <<");
        if (mTimer != null) {
            mTimer.cancel();
        }
    }
    private void trackLocation() {
        Log.e(TAG, "trackLocation");
        String TAG_TRACK_LOCATION = "trackLocation";
        Map<String, String> params = new HashMap<>();
        params.put("latitude", "" + track_lat);
        params.put("longitude", "" + track_lng);
        Log.e(TAG, "param_track_location >> " + params.toString());
        stopSelf();
        mTimer.cancel();
    }
    @Override
    public void onLocationChanged(Location location) {
    }
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    }
    @Override
    public void onProviderEnabled(String provider) {
    }
    @Override
    public void onProviderDisabled(String provider) {
    }
    /******************************/
    private void fn_getlocation() {
        locationManager = (LocationManager) getApplicationContext().getSystemService(LOCATION_SERVICE);
        isGPSEnable = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        isNetworkEnable = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
        if (!isGPSEnable && !isNetworkEnable) {
            Log.e(TAG, "CAN'T GET LOCATION");
            stopSelf();
        } else {
            if (isNetworkEnable) {
                location = null;
                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 0, this);
                if (locationManager != null) {
                    location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        Log.e(TAG, "isNetworkEnable latitude" + location.getLatitude() + "\nlongitude" + location.getLongitude() + "");
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                        track_lat = latitude;
                        track_lng = longitude;
//                        fn_update(location);
                    }
                }
            }
            if (isGPSEnable) {
                location = null;
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this);
                if (locationManager != null) {
                    location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                    if (location != null) {
                        Log.e(TAG, "isGPSEnable latitude" + location.getLatitude() + "\nlongitude" + location.getLongitude() + "");
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                        track_lat = latitude;
                        track_lng = longitude;
//                        fn_update(location);
                    }
                }
            }
            Log.e(TAG, "START SERVICE");
            trackLocation();
        }
    }
    private class TimerTaskToGetLocation extends TimerTask {
        @Override
        public void run() {
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    fn_getlocation();
                }
            });
        }
    }
//    private void fn_update(Location location) {
//
//        intent.putExtra("latutide", location.getLatitude() + "");
//        intent.putExtra("longitude", location.getLongitude() + "");
//        sendBroadcast(intent);
//    }
}
AlarmReceive.java (BroadcastReceiver)
public class AlarmReceive extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Log.e("Service_call_"  , "You are in AlarmReceive class.");
        Intent background = new Intent(context, BookingTrackingService.class);
//        Intent background = new Intent(context, GoogleService.class);
        Log.e("AlarmReceive ","testing called broadcast called");
        context.startService(background);
    }
}
AndroidManifest.xml
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
 <service
            android:name=".ServiceAndBroadcast.BookingTrackingService"
            android:enabled="true" />
        <receiver
            android:name=".ServiceAndBroadcast.AlarmReceive"
            android:exported="false">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
        </receiver>