Write to File After Closing

As part of an assignment, I have to write to a file after my JFrame component closes. Right now, it will write to a file regardless of its visibility. Here is my write method:

Code:

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        public static void write(String text){
                FileWriter fw = null;
                PrintWriter pw = null;
                try{
                        fw = new FileWriter("updated_contacts.txt", true);
                        pw = new PrintWriter(fw);
                        pw.println(text);       
                        pw.close();
                }catch (IOException e){
                        JOptionPane.showMessageDialog(null, "File 'updated_contacts.txt' not found.", "Error", JOptionPane.ERROR_MESSAGE);
                }
        }

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I also have an actionPerformed method, but this simply calls the method above with a string as its parameter. Nonetheless, I will provide the code if requested.

Thanks.
Ben

Code:

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jframe.addWindowListener(new WindowAdapter() {
    public void windowClosed(WindowEvent e) {
        //code when jframe closes
    }
});

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Solution:

Code:

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public class MyFrame extends JFrame{ //class
        ...
        public MyFrame(){ //constructor
                listenToWindow(); //call method
                ...
        public void listenToWindow(){ //method
                addWindowListener //execute my window listener
                  (new WindowAdapter(){ //used WindowAdapter
                        public void windowClosing(WindowEvent e){ //an inherited method from class WindowListener
                          setTitle("Closing window..."); //change current title to identify that it is closing
                          try{
                                Thread.sleep(SLEEP);
                          }catch (InterruptedException error){
                                System.out.println(error.getMessage());
                          }
                          for (int i=0; i<list.getModel().getSize(); i++) //get size of list
                            ioStream.write((String)list.getModel().getElementAt(i)); //write current size of list to updated_contacts.txt
                          setVisible(false); //frame is no longer viewable
                          dispose(); //eliminate frame
                          System.exit(0); //dispose process
                        }
                  });
        }

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Much thanks ra4king.

Glad to help :)