Preference behavior is unpredictable..

Question

I use this couple of classes to store the state of windows..
but not the state of every windows is saved.. can some one tell me why?
the think that i don't understand is the unpredicatble behavior of the system..
some time the new preferences are stored sometime not
thanks...
* JFClient.java
* Created on February 15, 2006, 4:31 PM
package util;
* @author  dimitri
public class JFClient extends javax.swing.JFrame {
    /** Creates new form JFClient */
    public JFClient() {
        //initComponents();
        JFCManager.getJFCManager().addClient(this);
    public JFClient(String _par) {
        super(_par);
        //initComponents();
        JFCManager.getJFCManager().addClient(this);
    public String getJFClientKEY(){
        return getTitle();
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
    // <editor-fold defaultstate="collapsed" desc=" Generated Code ">                         
    private void initComponents() {
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        pack();
    // </editor-fold>                       
    // Variables declaration - do not modify                    
    // End of variables declaration                  
* JFCManager.java
* Created on 19 marzo 2006, 19.26
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
package util;
import java.awt.Component;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Set;
import java.util.prefs.BackingStoreException;
import java.util.prefs.Preferences;
* @author Dimitri
public class JFCManager extends ComponentAdapter implements java.io.Serializable{
    private final Preferences p;
    final Hashtable<Component,Integer> clientsTable;
    private static JFCManager instance;
    /** Creates a new instance of JFCManager */
    public JFCManager(String _node) {
        p=Preferences.userRoot().node(_node);
        try {
            p.flush();
        } catch (BackingStoreException ex) {
            ex.printStackTrace();
        clientsTable=new Hashtable<Component,Integer> ();
        instance=this;
    static public JFCManager getJFCManager() {
        return instance;
    public void addClient(JFClient client){
        Integer key=Integer.valueOf(client.getJFClientKEY().hashCode());
        System.out.println(client.getJFClientKEY()+" "+client.getJFClientKEY().hashCode());
        clientsTable.put(client,key);
        client.addComponentListener(this);
    public void removeClient(JFClient client){
        client.removeComponentListener(this);
    public void componentMoved(ComponentEvent componentEvent) {
        Component compo=componentEvent.getComponent();
        java.awt.Point point =compo.getLocation();
        if(clientsTable.containsKey(compo)){
            Integer key=(Integer)clientsTable.get(compo);
            p.putInt(key+"_x",point.x);
            p.putInt(key+"_y",point.y);
            try {
                p.flush();
            } catch (BackingStoreException ex) {
                ex.printStackTrace();
    public void componentResized(ComponentEvent componentEvent) {
        Component compo=componentEvent.getComponent();
        int w =compo.getWidth();
        int h =compo.getHeight();
        if(clientsTable.containsKey(compo)){
            Integer key=(Integer)clientsTable.get(compo);
            p.putInt(key+"_width",w);
            p.putInt(key+"_height",h);
            try {
                p.flush();
            } catch (BackingStoreException ex) {
                ex.printStackTrace();
    public void componentHidden(ComponentEvent componentEvent) {
        Component compo=componentEvent.getComponent();
        int w =compo.getWidth();
        int h =compo.getHeight();
        if(clientsTable.containsKey(compo)){
            Integer key=(Integer)clientsTable.get(compo);
            p.putBoolean(key+"_visible",false);
            try {
                p.flush();
            } catch (BackingStoreException ex) {
                ex.printStackTrace();
    public void componentShown(ComponentEvent componentEvent) {
        Component compo=componentEvent.getComponent();
        int w =compo.getWidth();
        int h =compo.getHeight();
        if(clientsTable.containsKey(compo)){
            Integer key=(Integer)clientsTable.get(compo);
            p.putBoolean(key+"_visible",false);
            try {
                p.flush();
            } catch (BackingStoreException ex) {
                ex.printStackTrace();
            restoreComponentStatus(key,(JFClient)compo);
    protected void restoreComponentStatus(Integer key,JFClient client){
        int w,h,x,y;
        boolean visible;
        w=p.getInt(key+"_width",100);
        h=p.getInt(key+"_height",100);
        x=p.getInt(key+"_x",100);
        y=p.getInt(key+"_y",100);
        visible=p.getBoolean(key+"_visible",true);
        client.setSize(w,h);
        client.setLocation(x,y);      
    public void restore(){
        Set<Entry<Component,Integer>> s=clientsTable.entrySet();       
        Iterator<Entry<Component,Integer>>i=s.iterator();
        while(i.hasNext()){
            Entry<Component,Integer>e=i.next();
            if(e.getKey()!=null)
                restoreComponentStatus(e.getValue(), (JFClient) e.getKey());
    public Preferences getP() {
        return p;
}

Answer 1

Are you sure that the hashcodes of the titles are matching what is stored in the preferences?