Change color on focus

Hello everyone out there, another question.

I realized I need to ask you questions so you have them to answer!


How can I get the Jpanels color to get set on focus




import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class MyClass4 extends JPanel {
  JLabel jLabel1;  
 
  ArrayList myArrayList = new ArrayList();

// Constructor
public MyClass4() {

    setLayout(new GridLayout(0,3)); // Setting MY layout...

add(jLabel1);  jLabel1.setText("Defensive Moves"); setBackground(Color.white);

    looprow:
        for (int row=0; row<20; row++) {
            for(int col=0; col<3; col++) {
                int n=(20*col+row+1);
                if (n>50) break looprow;
                JCheckBox check = new JCheckBox("" + n);

            myArrayList.add(check);
add(check); // Adding it to ME
}
}
}
}