MouseEvent.BUTTON2 has the following syntax.
public static final int BUTTON2
In the following code shows how to use MouseEvent.BUTTON2 field.
/* www . j a va2 s . com*/ import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel { JButton button = new JButton("I Move"); public Main() { setLayout(null); add(button); button.setSize(button.getPreferredSize()); button.setLocation(20, 20); addMouseListener(new MouseAdapter() { public void mousePressed(MouseEvent e) { System.out.println(e.getButton() == MouseEvent.BUTTON2); } }); } 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 Main()); frame.setVisible(true); } }