How to reorganize JCombobox depends on prior choice (Java Swing)

I'm about to make selection menus consist of 3 JComboboxes, and they are related to prior choice.<br>
When I choose first menu, I need to update next JCombobox by requesting JSON, and so on for last menu.<br>
What I tried : put addActionListener to update next JCombobox, but it seems not working.<br>
It's hard to find problem as I cannot catch it through debugger.<br>
The method 'getParsedData' returns JSONArray came from JSON file.

        JPanel test = new JPanel();
        test.setLayout(new FlowLayout());
        add(test);

        top = rc.getParsedData("top");
        ArrayList<String> topList = rc.getLocationList(top);
        location1 = new JComboBox(topList.toArray(new String[topList.size()]));
        location1.addActionListener(e -> {
            try {
                rc.setCode(top, location1.getSelectedItem().toString());
                mdl = rc.getParsedData("mdl");
                ArrayList<String> mdlList = rc.getLocationList(mdl);
                location2 = new JComboBox(mdlList.toArray(new String[mdlList.size()]));
            } catch (IOException | ParseException ioException) {
                ioException.printStackTrace();
            }
        });

        test.add(location1);
        
        location2.addActionListener(e -> {
            try {
                leaf = rc.getParsedData("leaf");
                rc.setCode(mdl, location2.getSelectedItem().toString());
                ArrayList<String> leafList = rc.getLocationList(leaf);
                location3 = new JComboBox(leafList.toArray(new String[leafList.size()]));
                rc.setXY(leaf, location3.getSelectedItem().toString());
            } catch (IOException | ParseException ioException) {
                ioException.printStackTrace();
            }
        });
        test.add(location2);
        
        test.add(location3);

Instead of creating a new JComboBox each time the ActionListener gets active (using <code>new JComboBox(...))</code> you should update the existing location2/location3-instances.

For location2 you can do that by first calling
<code>location2.removeAllItems()</code>. Afterwards you should iterate over your mdList and call <code>location2.addItem()</code> for each mdList-item.