Null layout manager example from Oreilly

//file: MoveButton.java
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
 
    public class MoveButton extends JPanel {
      JButton button = new JButton("I Move");
 
      public MoveButton() {
        setLayout(null);
        add(button);
        button.setSize(button.getPreferredSize());
        button.setLocation(20, 20);
        addMouseListener(new MouseAdapter() {
          public void mousePressed(MouseEvent e) {
          button.setLocation(e.getX(), e.getY());
          }
        });
      }
 
      public static void main(String[] args) {
        JFrame frame = new JFrame("MoveButton");
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.setSize(250, 200);
        frame.setLocation(200, 200);
        frame.setContentPane(new MoveButton());
        frame.setVisible(true);
      }
    }