Breadth-First and Depth-First Search Are Generating the Same Statistics

Question

I need to make a program that will automatically solve and display search statistics for an 8-puzzle problem using 4 different search algorithms: Breadth-First, Depth-First, Best-First and A star.

I am able to generate the correct statistics for BF search, Best-First search and A star search, but for some reason, my DF search algorithm is yielding the same statistics as the BF search. I am really stumped as to why this only happens with DF search.

I am using a ChoiceBox to allow the user to select which search algorithm to use, and the way I created the ChoiceBox and the ActionListener is shown here:

private VBox makeSearchTypeDropdown()
    {
        VBox searchTypeDropdown = new VBox();
        
        searchTypeLabel = new Label("Search Type");
        searchTypeLabel.setFont(new Font(14));
        
        String searchTypeNames[] = {"BF State Space Search", "DF State Space Search", "Best-First Search", "A* Search"};
        
        searchTypes = new ChoiceBox<>(FXCollections.observableArrayList(searchTypeNames));
        
        
        searchTypeDropdown.setPadding(new Insets(10, 10, 10, 10));
        searchTypeDropdown.setAlignment(Pos.CENTER);
        searchTypeDropdown.getChildren().addAll(searchTypeLabel, searchTypes);
        
        
        
        return searchTypeDropdown;
    }

private void addSearchSelectListener()
    {
        searchTypes.setOnAction(e -> {
            
            switch((String) searchTypes.getValue())
            {
                case "BF State Space Search":
                    curSolver = new BFSStateSpaceSolver(prob); //curSolver is of an abstract solver type
                    break;
                case "DF State Space Search":
                    curSolver = new DFSStateSpaceSolver(prob);
                    break;
                case "Best-First Search":
                    curSolver = new BestFirstSolver(prob);
                    break;
                case "A* Search":
                    curSolver = new AStarSolver(prob);
                    break;
            }
        });
    }

I'm not too sure if this will be useful to include or not, but here is the code that was provided to use depth-first search:

public class DFSStateSpaceSolver extends StateSpaceSolver {
    
    public DFSStateSpaceSolver(Problem problem) {
        super(problem);
        super.getStatistics().setHeader("Depth-First Search");
    }
    
    @Override
    public void add(Vertex v) {
        ((LinkedList<Vertex>)getQueue()).addFirst(v); // DFS
    }
    
}

Thank you for the help!