Using EWS to send mail from exchange server

Question

I followed this link to generate the jar file. I added this to my project. Then have a simple code to send a mail:

public void mailSend() {
        ExchangeService service = new ExchangeService();
        ExchangeCredentials credentials = new WebCredentials(
                "email", "$*pass!");
        service.setCredentials(credentials);

        String host = "host";
        try {
            service.setUrl(new java.net.URI("https://" + host
                    + "/EWS/Exchange.asmx"));

            service.setTraceEnabled(true);

            EmailMessage msg = new EmailMessage(service);
            msg.setSubject("Hello world!");
            msg.setBody(MessageBody
                    .getMessageBodyFromText("Sent using the EWS Managed API."));
            msg.getToRecipients().add("email");
            msg.send();
            Log.i("Msg","SEND   ");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
}

The problem is that it shows the jar file has no source attachment. Hence I get the error no definition found for class ExchangeService. This should be part of the jar file generated. While exporting as jar file, I had made sure the src folder is clicked.