I think it can be related to "implementation of the abstract class".
Try this:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
public class ExamButton extends JFrame {
JButton button_32 = new JButton("ssf");
JFrame frame = new JFrame();
public ExamButton() {
final JButton button_32 = new JButton("2");
button_32.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
button_32.setBackground(Color.red);
}
});
button_32.setBounds(0, 57, 33, 29);
add(button_32, BorderLayout.CENTER);
setSize(300, 300);
setVisible(true);
}
public static void main(String[] args) {
new ExamButton();
}
}