Saving changes in App...

Question

I have an app with a several JPanels. On each JPanel are several smaller JPanels that can be dragged around. Each time I start the app the draggable JPanels are located at the position they were coded in at (with the 'setBounds' method).
Each time the app is opened I need the JPanels to be at the location they were at when the app last closed.
Can someone please HELP??? thanks...

Answer 1

i tried writing out the X and Y coordinates of the JPanels and then reading them back in at startup but no matter where the JPanel is the coordinates are always written out as 0.
heres how I'm doing it...
frame.setDefaultCloseOperation(frame.DO_NOTHING_ON_CLOSE);
frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
      writeoutbutton.doClick(); //button carrying out write action
writeoutbutton.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent e) {
try{
int n = JOptionPane.showConfirmDialog(frame, "Save Changes Before Exiting?", "Save?", JOptionPane.YES_NO_CANCEL_OPTION);
if (n == JOptionPane.YES_OPTION) {
DataOutputStream out = new DataOutputStream(new FileOutputStream("file.dat"));
out.writeInt(jpanel.getX());  //same process for Y coordinate
out.flush();
out.close();
System.exit(0);
}else if (n == JOptionPane.NO_OPTION) {
          System.exit(0);
}else {}
}catch(Exception a){}
// then reading in at startup...
DataInputStream in = new DataInputStream(new FileInputStream("file.dat"));
jPanel.setLocation(in.readInt(), same process for Y coordinate);
}});everytime I run this and restart the app, the JPanel is at the 0,0 location of its container(it also prints 0 for the coordinate using... System.out.println(in.readInt());
help please??