import java.awt.Component;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JButton;
import javax.swing.JFrame;
class MouseEnterFocusMover extends MouseAdapter {
public void mouseEntered(MouseEvent mouseEvent) {
Component component = mouseEvent.getComponent();
if (!component.hasFocus()) {
component.requestFocusInWindow();
}
}
}
public class FocusSampleMouseEnterFocusMover {
public static void main(String args[]) {
JFrame frame = new JFrame("Focus Sample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MouseListener mouseListener = new MouseEnterFocusMover();
frame.setLayout(new GridLayout(3, 3));
for (int i = 1; i < 10; i++) {
JButton button = new JButton(Integer.toString(i));
button.addMouseListener(mouseListener);
if ((i % 2) != 0) {
button.setFocusable(false);
}
frame.add(button);
}
frame.setSize(300, 200);
frame.setVisible(true);
}
}