how to change the jbutton color while it is in focus?

refer to this code~

import java.awt.GridLayout;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class ButtonPane extends JPanel {

private JButton[][] buttons;

public ButtonPane(int row, int col) {
super(new GridLayout(row, col));
buttons = new JButton[row][col];
for (int i = 0; i < buttons.length; i++) {
for (int j = 0; j < buttons[i].length; j++) {
final int curRow = i;
final int curCol = j;
buttons[i][j] = new JButton(i + ", " + j);
buttons[i][j].addKeyListener(enter);
buttons[i][j].addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
if (curRow > 0)

buttons[curRow - 1][curCol].requestFocus();
break;
case KeyEvent.VK_DOWN:
if (curRow < buttons.length - 1)
buttons[curRow + 1][curCol].requestFocus();
break;
case KeyEvent.VK_LEFT:
if (curCol > 0)
buttons[curRow][curCol - 1].requestFocus();
break;
case KeyEvent.VK_RIGHT:
if (curCol < buttons[curRow].length - 1)
buttons[curRow][curCol + 1].requestFocus();
break;
default:
break;
}
}
});
add(buttons[i][j]);
}
}
}

private KeyListener enter = new KeyAdapter() {
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyChar() == KeyEvent.VK_ENTER) {
((JButton) e.getComponent()).doClick();
}
}
};

public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new ButtonPane(4, 4));
f.pack();
f.setVisible(true);
}
}

add a FocusListener:
focusGained() change to whatever color you want
focusLost() change back to normal

ok let say,
my button gained focus and changed its color,
how if later it lost focus?it still remains the changed color or it will change to the previous

> or it will change to the previous

it will, if you code it that way

thank you.^^

- dont to use FocusListener or MouseListener for this job

- this methods are implemented in the JButton API directly & correctly

- you can to implememt ChangeListener with taking a proper event (mouse & key too) from ButtonModel (isArmed, selected, ....)