show.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                doDisplay();
            }
        });

private void doDisplay(){
        JOptionPane.showMessageDialog(this, "Username: " + tUsername.getSelectedText() + "n" + "Email: " + tEmail.getSelectedText() + "n" + "Password: " + tPassword.getSelectedText(), "JDIALOG", JOptionPane.INFORMATION_MESSAGE);
    }