public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        checkLocationPermission();
        Log.d(TAG, "Permission has been checked!");

        Position position = new Position(this);
        Log.d(TAG, "Latitude: ");
        String lat = position.getLatitude();
        Log.d(TAG, lat);  // zwraca java.lang.NullPointerException: println needs a message

    }

    private void checkLocationPermission() {
        if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
            openGetLocationPermission();
    }

    private void openGetLocationPermission() {
        Intent intent = new Intent(this, GetLocationPermission.class);
        startActivity(intent);
    }
}