Hashtable<String, String> ht = new Hashtable<String, String>();
        ht.put("1", "1");
        ht.put("2", "2");
        ht.put("3", "3");
        JTree jtree = new JTree(ht);
        pnlMain.add(jtree);
        
        jtree.addTreeSelectionListener(new TreeSelectionListener() {
            public void valueChanged(TreeSelectionEvent e) {
                System.out.println(e.getNewLeadSelectionPath());
            }
        });