import javax.swing.*;

import java.awt.*;

import javax.swing.border.EmptyBorder;

import javax.swing.plaf.basic.BasicButtonUI;

public class SquareButton extends JButton {

private static final Color BACKGROUND_COLOR = new Color(64, 64, 64);

public static final int BUTTON_SIZE = 64;

public SquareButton(String text) {

super(text);

setFocusPainted(true);

setPreferredSize(new Dimension(BUTTON_SIZE, BUTTON_SIZE));

setBackground(BACKGROUND_COLOR);

setBorder(new EmptyBorder(0, 0, 0, 0));

setUI(new BasicButtonUI());

}

@Override

public Dimension getPreferredSize() {

Dimension d = super.getPreferredSize();

int size = Math.max(d.width, d.height);

return new Dimension(size, size);

}

}