My test program :public class main { public static void main(String[] args) { PersonalSMTP.main(args); PersonalSMTP.addActionEventListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { System.out.println("New email :)"+arg0.getActionCommand()); } });}I have this error :Exception in thread "main" java.lang.NoSuchMethodError: com.ericdaugherty.mail.server.services.smtp.SMTPSender.addActionEventListener(Ljava/awt/event/ActionListener;)Code in my personalSMTP jar file :public class personalSMTP { private static SMTPSender smtpSender; /** The SMTP sender thread */ private static Thread smtpSenderThread; PersonalSMTP.main() { //Start the SMTPSender thread (This thread actually delivers the mail recieved //by the SMTP threads. smtpSender = new SMTPSender(); smtpSenderThread = new Thread( smtpSender, "SMTPSender" ); smtpSenderThread.start(); } //*************************************************************** // Event Method //*************************************************************** public static void addActionEventListener(ActionListener listener) { //xxxListeners.addElement(ActionListener.class); //xxxListeners.addElement(listener); smtpSender.addActionEventListener(listener); }}public class SMTPSender implements Runnable { /** Listener List */ private Vector xxxListeners = new Vector(); public void addActionEventListener(ActionListener listener) { xxxListeners.addElement(ActionListener.class); xxxListeners.addElement(listener); }}