JList prints duplicate values on console, display single values on GUI

Question

I was trying to troubleshoot the code that why JList prints same values x2 times on console, but on GUI it shows only x1 time. I need ID on backend to do more functions, but it comes x2 time. The values are retrieving from DB. JList Initialization & calling: -

CustomListModel listModel;
listModel = new CustomListModel(getListOfRoutes());
routeList = new JList<tbl_bom_route>(listModel);
ListSelectionListener myListener = new listListeners();
routeList.addListSelectionListener(myListener);
routeList.setCellRenderer(new routeListCellRenderer());
scrollPaneList.setViewportView(routeList);

class CustomListModel extends AbstractListModel<tbl_bom_route> {
        private static final long serialVersionUID = 1L;
        private ArrayList<tbl_bom_route> items;
        public CustomListModel(ArrayList<tbl_bom_route> items) {
            this.items = items;
        }
        @Override
        public int getSize() {
            return items.size();
        }

        @Override
        public tbl_bom_route getElementAt(int index) {
            return items.get(index);
        }
    }

 private ArrayList<tbl_bom_route> getListOfRoutes() {
            ArrayList<tbl_bom_route> itemsList = new ArrayList<>();
            try {
                itemsList = daoBomRouteObject.getAllListOfRoutes();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return itemsList;
        }

class routeListCellRenderer extends DefaultListCellRenderer {
        private static final long serialVersionUID = 1L;
        @Override
        public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected,
                boolean cellHasFocus) {
            super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
            if (value instanceof tbl_bom_route) {
                tbl_bom_route item = (tbl_bom_route) value;
                setText(item.getRouteName());
            }
            return this;
        }
    }

Console Output: -

• Route00476R1020ARDWN_No 4 Draw Bench
• ID186
• Route00476R1020ARDWN_No 4 Draw Bench
• ID186

Updated: -

private class RouteListListener implements ListSelectionListener {
        @Override
        public void valueChanged(ListSelectionEvent e) {
            if (!e.getValueIsAdjusting()) {
                int selectedIndex = routeList.getSelectedIndex();
                if (selectedIndex != -1) {
                    tbl_bom_route selectedListValue = routeList.getSelectedValue();
                    SANDBOX_GROUP_ID = selectedListValue.getRouteGroupID();
                }
            }
        }
    }