//file: Flow.javaimport java.awt.*;import java.awt.event.*;import javax.swing.*;public class Flow extends JPanel {  public Flow(  ) {    // FlowLayout is default layout manager for a JPanel    add(new JButton("One"));    add(new JButton("Two"));    add(new JButton("Three"));    add(new JButton("Four"));    add(new JButton("Five"));  }  public static void main(String[] args) {    JFrame f = new JFrame("Flow");    f.addWindowListener(new WindowAdapter(  ) {      public void windowClosing(WindowEvent e) { System.exit(0); }    });    f.setSize(400, 75);    f.setLocation(200, 200);    Flow flow = new Flow(  );    f.setContentPane(flow);    f.setVisible(true);  }}