Error with context

To start off with i'm a new coder with greenfoot and a new coder overall. I'm having an error where I can't reference a non-static method (Wall.getY) from a static context here is the code and the error appears at every .get I plan to use this to find the position of the walls for a game where it is one of those puzzle sliding games. One appears in pokemon yellow at some point. if(Wall.getY() == y--) if(Wall.getX() == x) return false; else if (Wall.getX() /= x) return true; else if(Wall.getY() == y) return true;