Java by API/javax.swing.border/CompoundBorder

new CompoundBorder(Border outsideBorder, Border insideBorder)

import java.awt.Color;
import java.awt.Container;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.border.Border;
import javax.swing.border.rupoundBorder;

public class MainClass {
  public static void main(final String args[]) {
    JFrame frame = new JFrame("Justified Titled Borders");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
    Border greenBorder = BorderFactory.createLineBorder(Color.GREEN, 2);
    Border blueBorder = BorderFactory.createLineBorder(Color.BLUE, 2);
    Border magentaBorder = BorderFactory.createLineBorder(Color.MAGENTA, 2);
    Border twoColorBorder = new CompoundBorder(magentaBorder, blueBorder);
    Border threeColorBorder = new CompoundBorder(twoColorBorder, greenBorder);
    JButton rainbowButton = new JButton("Rainbow");
    rainbowButton.setBorder(threeColorBorder);
    Container contentPane = frame.getContentPane();
    contentPane.add(rainbowButton);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}