Java JFrame set initial focused component

import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.Window;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;

public class Main {
   public static void main(String[] argv) throws Exception {
      JFrame frame = new JFrame();
      JButton component1 = new JButton("1");
      JButton component2 = new JButton("2");
      JButton component3 = new JButton("3");

      frame.setLayout(new FlowLayout());
      frame.add(component1);//  w w w .  j av a2 s.  c om
      frame.add(component2);
      frame.add(component3);

      setInitialFocus(frame, component2);

      frame.pack();
      frame.setVisible(true);
   }

   public static void setInitialFocus(Window w, Component c) {
      w.addWindowListener(new FocusSetter(c));
   }
}

class FocusSetter extends WindowAdapter {
   Component initComp;

   FocusSetter(Component c) {
      initComp = c;
   }

   public void windowOpened(WindowEvent e) {
      initComp.requestFocus();
      e.getWindow().removeWindowListener(this);
   }
}