How do I implement A* in Java?

Question

Here is what I have so far for my pathfinding algorithm:

public void AAlg(int a, int b){
        boolean bool=true;
        while(bool) {
            bool = false;
            for (int i = 0; i <map.length; i++) {
                for (int j = 0; j < map.length; j++) {
                    if(ifObj(i, j)) {
                        bool=true;
                    }
                }
            }
            int smallest=N;
            int[] coords = new int[2];
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if((i==1&&j==0)||(i==2&&j==1)||(i==1&&j==2)||(i==0&&j==1)) {
                        findFGH(i+a,j+b);
                        if(f<smallest) {
                            smallest=f;
                            coords[0]=i+a;
                            coords[1]=j+b;
                        }
                    }
                }
            }
            if(coords[0]==N-1&&coords[1]==.N-1) {
                System.out.println("The distance travelled is "+cnt);
            }
            AAlg(coords[0], coords[1]);
            cnt++;
        }

N is the length of the grid in both width and height, and map is well, the map. It is a boolean[][], with everything false except for where there are obstructions. I envisioned my code to somewhat just from square to square, iterating and finding the most efficient square to go to next. What it wrong? It just loops indefinitely.

Answer 1

This is not an answer to why your algorithm doesn't work but more a helpful source of material you could look at in order to work out how A* works in general. I implemented this algorithm in java a while ago and have recently upgraded it to java13 and put it on github here:

Github repo for A* algorithm project in java13

On top of this is a javafx visual test program where you can play around with the package created from the above module. This is found in the link below:

Git repo of A* visual test app

if you have maven set up to work with github the second project will automatically get the A* package from github i think.