Java Swing で JTextArea を超えてカスタム テキストの色付けを実現するにはどうすればよいですか?

import java.awt.Color;
import java.awt.Insets;
import java.awt.event.EmptyBorder;
import javax.swing.JTextPane;
import javax.swing.text.AttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;

public class TextColoringDemo {

    public void setTextColors() {
        JTextPane textPane = new JTextPane();
        textPane.setBorder(new EmptyBorder(new Insets(10, 10, 10, 10)));

        StyleContext styleContext = StyleContext.getDefaultStyleContext();
        AttributeSet blueAttributeSet = styleContext.addAttribute(
                SimpleAttributeSet.EMPTY,
                StyleConstants.Foreground,
                Color.BLUE
        );

        AttributeSet greenAttributeSet = styleContext.addAttribute(
                SimpleAttributeSet.EMPTY,
                StyleConstants.Foreground,
                Color.GREEN
        );

        AttributeSet redAttributeSet = styleContext.addAttribute(
                SimpleAttributeSet.EMPTY,
                StyleConstants.Foreground,
                Color.RED
        );

        AttributeSet orangeAttributeSet = styleContext.addAttribute(
                SimpleAttributeSet.EMPTY,
                StyleConstants.Foreground,
                Color.ORANGE
        );

        // Set the color of specific text sections
        textPane.setCharacterAttributes(blueAttributeSet, true);
        textPane.replaceSelection("LOAD R1, 1\n");
        textPane.setCharacterAttributes(blueAttributeSet, true);
        textPane.replaceSelection("DEC R1\n");
        textPane.setCharacterAttributes(blueAttributeSet, true);
        textPane.replaceSelection("STORE M, R1\n");
        textPane.setCharacterAttributes(blueAttributeSet, true);
        textPane.replaceSelection("ADD R4, R1,8\n");

        textPane.setCharacterAttributes(greenAttributeSet, true);
        textPane.replaceSelection("R1\n");
        textPane.setCharacterAttributes(greenAttributeSet, true);
        textPane.replaceSelection("R4\n");

        textPane.setCharacterAttributes(redAttributeSet, true);
        textPane.replaceSelection("M\n");

        textPane.setCharacterAttributes(orangeAttributeSet, true);
        textPane.replaceSelection("1\n");
        textPane.setCharacterAttributes(orangeAttributeSet, true);
        textPane.replaceSelection("8\n");
    }
}