Value Change Listener to JTextField

Question

I want the message box to appear immediately after the user changes the value in the textfield. Currently, I need to hit the enter key to get the message box to pop out. Is

Answer 1

textBoxName.getDocument().addDocumentListener(new DocumentListener() {
   @Override
   public void insertUpdate(DocumentEvent e) {
       onChange();
   }

   @Override
   public void removeUpdate(DocumentEvent e) {
      onChange();
   }

   @Override
   public void changedUpdate(DocumentEvent e) {
      onChange();
   } 
});

But I would not just parse anything the user (maybe on accident) touches on his keyboard into an Integer. You should catch any Exceptions thrown and make sure the JTextField is not empty.