Java Mail : No provider for smtp

I am using JavaMail to do a simple application that sends an email when it finds some files in a directory. I managed to get it worked from Eclipse. I Run the application and it sent the email with no errors.

But, when I created the jar, and executed it, it fails in the email sending part. It gives this exception:

javax.mail.NoSuchProviderException: No provider for smtp
 at javax.mail.Session.getProvider(Session.java:460)
 at javax.mail.Session.getTransport(Session.java:655)
 at javax.mail.Session.getTransport(Session.java:636)
 at main.java.util.MailManager.sendMail(MailManager.java:69)
 at main.java.DownloadsMail.composeAndSendMail(DownloadsMail.java:16)
 at main.java.DownloadsController.checkDownloads(DownloadsController.java:51)
 at main.java.MainDownloadsController.run(MainDownloadsController.java:26)
 at java.lang.Thread.run(Unknown Source)

I am using the library in this method:

public static boolean sendMail(String subject, String text) {

    noExceptionsThrown = true;
    try {
        loadProperties();
    } catch (IOException e1) {
        System.out.println("Problem encountered while loading properties");
        e1.printStackTrace();
        noExceptionsThrown = false;
    }

    Properties mailProps = new Properties();

    String host = "mail.smtp.host";
    mailProps.setProperty(host, connectionProps.getProperty(host));

    String tls = "mail.smtp.starttls.enable";
    mailProps.setProperty(tls, connectionProps.getProperty(tls));

    String port = "mail.smtp.port";
    mailProps.setProperty(port, connectionProps.getProperty(port));

    String user = "mail.smtp.user";
    mailProps.setProperty(user, connectionProps.getProperty(user));

    String auth = "mail.smtp.auth";
    mailProps.setProperty(auth, connectionProps.getProperty(auth));

    Session session = Session.getDefaultInstance(mailProps);
    //session.setDebug(true);

    MimeMessage message = new MimeMessage(session);

    try