private int[] findRandomEmptyCoordinates(IGameMap game) {
    ArrayList<int[]> empty_fields = new ArrayList<int[]>();
    game.foreachField((x, y, type) -> {
      if (type == FieldType.EMPTY) {
        boolean field_is_free = true;
        for (Item current_item : game.getItemsOnMap()) {
          if (current_item.getX() == x && current_item.getY() == y) {
            field_is_free = false;
          }
        }
        if (field_is_free) {
          empty_fields.add(new int[] { x, y });
        }
      }
    });

    if (empty_fields.size() > 0) {
      int spawn_index = Rnd.nextInt(empty_fields.size());
      int[] spawn_location = empty_fields.get(spawn_index);
      return spawn_location;
    }
    return null;
  }