How to set border around a specific JPanel in a JFrame?

Question

I do not understand well, but I will do my best.

Basically, I am trying to add a border around mine JLabel, JTextFieldand JButtoncomponents in mine JPanel, however, the border expands to fit the size.

This is my code:

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

public class LoginPanel
{
    private JPanel loginPanel = new JPanel();
    private JFrame loginFrame = new JFrame();

    public LoginPanel()
    {
        loginPanel.setLayout(new GridBagLayout());

        GridBagConstraints gridBagConstraints = new GridBagConstraints();

        JTextField textLogin = new JTextField(10);
        JPasswordField password = new JPasswordField(10);

        JButton login = new JButton("Login");
        JButton register = new JButton("Register");

        gridBagConstraints.insets = new Insets(0,0,0,0);

        gridBagConstraints.gridy = 0;
        gridBagConstraints.gridx = 0;

        loginPanel.setBorder(BorderFactory.createTitledBorder("Login"));

        loginPanel.add(new JLabel("E-Mail"), gridBagConstraints);
        gridBagConstraints.gridy++;
        loginPanel.add(textLogin, gridBagConstraints);
        gridBagConstraints.gridy++;

        loginPanel.add(new JLabel("Password"), gridBagConstraints);
        gridBagConstraints.gridy++;
        loginPanel.add(password, gridBagConstraints);
        gridBagConstraints.gridy++;

        loginPanel.add(login, gridBagConstraints);
        gridBagConstraints.gridy++;
        loginPanel.add(register, gridBagConstraints);

        loginFrame.pack();
        loginFrame.add(loginPanel);
        loginFrame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        loginFrame.setLocationRelativeTo(null);
        loginFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        loginFrame.setVisible(true);
    }

    public static void main(String[] args)
    {
        try
        {
          UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch(Exception e)
        {
            e.printStackTrace();
        }

        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                new LoginPanel();
            }
        });
    }
}

This is the result:

I want the border to be like this:

I hope that the images explain more, I will answer and provide some more questions.

Answer 1

BorderLayout. , , CENTER. .

, :

    loginFrame.pack();

To:

    loginFrame.setLayout(new GridBagLayout());
    loginFrame.pack();

, GridBagLayout , .

:

, . , .

, :

    gridBagConstraints.insets = new Insets(0, 0, 0, 0);

To:

    gridBagConstraints.insets = new Insets(5, 5, 5, 5);

, EmptyBorder TitledBorder.

    Border border = new CompoundBorder(
            new TitledBorder("Login"), 
            new EmptyBorder(40, 50, 40, 50));
    loginPanel.setBorder(border);
    //loginPanel.setBorder(BorderFactory.createTitledBorder("Login"));

Answer 2

GridBagLayout :

    ...
    loginFrame.setLayout(new GridBagLayout());
    loginFrame.add(loginPanel, new GridBagConstraints(
        0, 0,
        1, 1, 
        0.0, 0.0, 
        GridBagConstraints.CENTER, GridBagConstraints.NONE, 
        new Insets(0, 0, 0, 0), 40, 20));
    ...

JFrame BorderLayout - CENTER . GridBagLayout, .