Java Swing - 如何使用默认BorderLayout定义容器最小大小

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JFrame {

  private static final long serialVersionUID = 1L;

  public Main() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }

  public void display() {
    add(new CustomComponents());
    pack();
    setMinimumSize(getSize());
    setVisible(true);
  }

  public static void main(String[] args) {
    Main main = new Main();
    main.display();
  }
}

class CustomComponents extends JPanel {

  private static final long serialVersionUID = 1L;

  @Override
  public Dimension getMinimumSize() {
    return new Dimension(100, 100);
  }

  @Override
  public Dimension getPreferredSize() {
    return new Dimension(400, 300);
  }

  @Override
  public void paintComponent(Graphics g) {
    int margin = 10;
    Dimension dim = getSize();
    super.paintComponent(g);
    g.setColor(Color.red);
    g.fillRect(margin, margin, dim.width - margin * 2, dim.height - margin * 2);
  }
}