Java JTextField handle focus event

import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;

import javax.swing.JFrame;
import javax.swing.JTextField;

public class Main {

   public static void main(String[] a) {
      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      JTextField textField = new JTextField("A TextField");
      textField.addFocusListener(new FocusListener() {
         public void focusGained(FocusEvent e) {
            System.out.println("focus gained " + (e.isTemporary() ? " (temporary):" : ":")
                  + e.getComponent().getClass().getName() + "; Opposite component: "
                  + (e.getOppositeComponent() != null ? e.getOppositeComponent().getClass().getName() : "null"));
         }/*from w  ww  .  j a va2 s. c o m*/

         public void focusLost(FocusEvent e) {
            System.out.println("focus lost " + (e.isTemporary() ? " (temporary):" : ":")
                  + e.getComponent().getClass().getName() + "; Opposite component: "
                  + (e.getOppositeComponent() != null ? e.getOppositeComponent().getClass().getName() : "null"));
         }
      });

      frame.add(textField, "North");
      frame.add(new JTextField(), "South");
      frame.setSize(300, 200);
      frame.setVisible(true);
   }

}