我有一个JTREE的界面，当改变界面内容后(增减节点），想保存改动，下次启动时用改动后的界面，
class Tree{
      Tree(){   load();

                jTree1=new JTree(top);

                //when first time use,init the tree with sample,or init the
                //tree with the load date.
                createNodes(top);
                treemodel=(DefaultTreeModel)jTree1.getModel();
                jTree1.setBorder(BorderFactory.createEtchedBorder());
                jTree1.setEditable(true);

                //set the tree single selected once
                jTree1.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
                jTree1.setRowHeight(26);

                //extend the root
                jTree1.setShowsRootHandles(true);

                //when extend a node, chicked 1 time
                jTree1.setToggleClickCount(1);


                jTree1.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(MouseEvent e) {
jTree1_mouseClicked(e);
}
});
                jTree1.addTreeSelectionListener(new javax.swing.event.TreeSelectionListener() {
                                 public void valueChanged(TreeSelectionEvent e) {
                                        jTree1_valueChanged(e);
                                 }
                         });
                jPopupMenu1.add(jMenu1);
        jPopupMenu1.add(jMenuItem2);
        jPopupMenu1.add(jMenuItem3);
        jMenu1.add(jMenuItem1);
        jMenu1.add(jMenuItem4);
                jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
                                           public void actionPerformed(ActionEvent e) {
                                                   jMenuItem1_actionPerformed(e);
                                                   }
                                              });
                jMenuItem4.addActionListener(new java.awt.event.ActionListener() {
                                           public void actionPerformed(ActionEvent e) {
                                                   jMenuItem4_actionPerformed(e);
                                                   }
                                              });
                jMenuItem2.addActionListener(new java.awt.event.ActionListener() {
                                           public void actionPerformed(ActionEvent e) {
                                                     jMenuItem2_actionPerformed(e);
                                                     }
                                              });
                jMenuItem3.addActionListener(new java.awt.event.ActionListener() {
                                             public void actionPerformed(ActionEvent e) {
                                                     jMenuItem3_actionPerformed(e);
                                                     }
                                              });


        }

//method createNodes to add nodes to the tree
public void createNodes(DefaultMutableTreeNode top) {

                //create the items in the tree
                DefaultMutableTreeNode node = null;
        DefaultMutableTreeNode child = null;

                node = new DefaultMutableTreeNode("News");
top.add(node);
child = new DefaultMutableTreeNode("www.sina.com.cn");
node.add(child);

node = new DefaultMutableTreeNode("Sports");
top.add(node);
child = new DefaultMutableTreeNode("www.fifa.com");
node.add(child);


}
        .
        .
        .
        .
        .


 //save the jTree1 to a sys file
         void save(){
          try{
               FileOutputStream fout=new FileOutputStream("address.bat");
               ObjectOutputStream out=new ObjectOutputStream(fout);
               out.writeObject(jTree1);
           }catch(Exception ed){}

         }

         //load the jTree date from the sys file
         void load(){
          try{
              FileInputStream fin=new FileInputStream("address.bat");
              ObjectInputStream in=new ObjectInputStream(fin);
              jTree1=(JTree)in.readObject();
            }catch(Exception er){}

         }
        .
        .
        .
        .
        .
但是重启动后界面不变，sava(),load(),也执行过，load()放在其他地方也有问题
请指教

没有见表示状态的实例变量的定义，怎摸保存状态，