public synchronized boolean removeItem(FieldItem item, Position position){
        if ((position.getX() <= this.getXLength()) || (position.getY() <= this.getYLength())) return false;
        if (field[position.getX()][position.getY()] == item) {
            field[position.getX()][position.getY()] = null;
            return true;
        }
        return false;
    }