title: JFrame very small using null layout
body: <p>Hi I am writing a simple program to display a frame.
  However the frame turns out real small when I type setLayout(null);
  But if i ignore this command, the button is always at the top center
  Can some one point out my error?</p>
  
  <pre><code>import java.io.*;
  import javax.swing.*;
  import java.awt.event.*;
  import java.awt.*;
  
  class theframe {
  
      private static void create() {
          JFrame frame = new JFrame("FrameDemo");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          Insets insets = frame.getInsets();
          frame.setSize(500 + insets.left + insets.right, 350 + insets.top + insets.bottom);
          add(frame.getContentPane()); //my function add
          frame.pack();
          frame.setVisible(true);
      }
  
      public static void add(Container pane) {
          pane.setLayout(null);
          Insets insets = pane.getInsets();
  
          JPanel p1 = new JPanel();
          p1.setPreferredSize(new Dimension(500, 350));
  
          JButton b1 = new JButton("one");
          Dimension size = b1.getPreferredSize();
          b1.setBounds(25 + insets.left, 5 + insets.top, size.width, size.height);
  
          pane.add(p1);
          p1.add(b1);
      }
  
      public static void main(String Args[]) {
          javax.swing.SwingUtilities.invokeLater(new Runnable() {
              public void run() {
                  create();
              }
          });
      }
  }
  </code></pre>