@Override
        public void actionPerformed(ActionEvent event) {
            
            String string = "";
            
            if(event.getSource() == textField1) {
                string = String.format("textField1: %s",
                        event.getActionCommand());
            }
            
            else if(event.getSource() == textField2) {
                string = String.format("textField2: %s",
                        event.getActionCommand());
            }
            
            else if(event.getSource() == textField3) {
                string = String.format("textField3: %s",
                        event.getActionCommand());
            }
            
            else if(event.getSource() == passwordField) {
                string = String.format("passwordField: %s",
                        event.getActionCommand());
            }
            
            JOptionPane.showMessageDialog(null, string);
            
        }