What is better way of setting up a map for a java 2D topdown game? Would it be having an ArrayList of tiles, a simple 2D array, a HashMap? (Note: the tiles/blocks or whatever are squared)
It depends on what you need to store. If you just want the positions of the tiles, a 2D array is probably the easiest way to store it (unless you have a dynamic world size). If you want the connections (for movement costs, etc.) then a Graph is probably what you want to use.