public Window() {
        initComponents();
        Reaction r = new Reaction (jButton1);
        jButton1.addMouseListener(r);
    }

package simple;
 
import java.awt.event.*;
import javax.swing.*;
 
public class Reaction implements MouseListener
{
    private JButton button;
 
    public Reaction (JButton b)
    {
        button = b;
    }
 
    public void mouseClicked(MouseEvent e) 
    {
        button.setText ("clicked");
    }
 
    public void mousePressed(MouseEvent e) 
    {
        button.setText ("pressed");
    }
 
    public void mouseReleased(MouseEvent e) 
    {
        button.setText ("released");
    }
 
    public void mouseEntered(MouseEvent e) 
    {
        button.setText ("entered");
    }
 
    public void mouseExited(MouseEvent e) 
    {
        button.setText ("exited");
    }
 
}