15 puzzle using 2d arrays

[GPB]

I made a basic (not very efficient) algorithm to solve a 15-puzzle using bfs.
Each node is a puzzle-state.

I assume I'm doing something wrong, because the puzzles.size() runs over 30000+
I'd really appreciate it if someone could take a look.

It should basically go:

new queue, add rootNode
while (queue != empty){
    Node n = firstFromQueue
    if ( n matches goalState)
        succes
    else
        add n.successors to queue

but also keep track of the nodes visited, because you don't need to visit them again.

[Norm]

Add some debugging statements to show execution flow and how variable values change.

If you see how the code is executing, you should be able to see your problem.