ButtonApp3 (other files are same as before): TextButton.java

import java.awt.*;

/**
 * Base class for our buttons that have text labels
 */
public abstract class TextButton extends Button {
    public TextButton (Square square, Square.ButtonAction action, String label) {
	super (square, action); //*2 Pass required arg to chained constructor
	setText (label); //*1 Common to all our text buttons
	setFont (new Font("SansSerif", Font.ITALIC, 14)); //*1
	setForeground (Color.BLUE); //*1
    }
}

[download file]