gridbag layout

I was recently studying GridBagLayout. As I have insuffecient material
ab GridBagLayout, I tried to learn from experiments.

Here is a code I wrote,

import javax.swing.*;
import java.awt.*;

public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        JFrame frm = new JFrame("Login");
        frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();

        JLabel loginHeading = new JLabel("Login Window");
        JLabel userId = new JLabel("User Id : ");
        JLabel passwd = new JLabel("Password : ");

        JButton login = new JButton("Login");

        JTextField userIdField = new JTextField(10);
        JTextField passwdField = new JTextField(10);

        GridBagLayout gbg = new GridBagLayout();
        GridBagConstraints gbc = new GridBagConstraints();
        frm.setLayout(gbg);

        gbc.anchor = GridBagConstraints.NORTH;
        gbc.insets = new Insets(25,25,0,0);

        gbc.gridwidth = GridBagConstraints.REMAINDER;
        gbg.setConstraints(loginHeading, gbc);

        gbc.gridwidth = GridBagConstraints.RELATIVE;
        gbg.setConstraints(userId, gbc);
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        gbg.setConstraints(userIdField, gbc);

        gbc.gridwidth = GridBagConstraints.RELATIVE;
        gbg.setConstraints(passwd, gbc);
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        gbg.setConstraints(passwdField, gbc);

        gbc.gridwidth = GridBagConstraints.REMAINDER;
        gbg.setConstraints(login, gbc);

        frm.add(loginHeading);
        frm.add(userId);
        frm.add(userIdField);
        frm.add(passwd);
        frm.add(passwdField);
        frm.add(login);

        //frm.pack();
        frm.setSize(400,500);
        frm.setVisible(true);

    }

}

It works fine. But how can I add spacing between the heading label and
the rest of the labels ???