Here you go

public class MyJButton extends JButton {

    public MyJButton() {
        this.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });
    }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        // Code à faire lors du clic
    }
}