private Session getSession(String smtpHost, String smtpPort, final String smtpUser, final String smtpPassword,
                               String encryption, String auth, String trust, String debug) {
        logger.debug("smtpHost = " + smtpHost);
        logger.debug("smtpPort = " + smtpPort);
        logger.debug("smtpUser = " + smtpUser);
        logger.debug("smtpPass = " + smtpPassword);
        logger.debug("encryption = " + encryption);
        logger.debug("auth = " + auth);
        logger.debug("trust = " + trust);
        logger.debug("debug = " + debug);

        Properties properties = new Properties();
        properties.put("mail.smtp.host", smtpHost);
        properties.put("mail.smtp.port", smtpPort);
        if (!Strings.isNullOrEmpty(auth)) {
            properties.put("mail.smtp.auth", auth);
        }
        if (!Strings.isNullOrEmpty(trust)) {
            properties.put("mail.smtp.ssl.trust", trust);
        }
        if (!Strings.isNullOrEmpty(debug)) {
            properties.put("mail.debug", debug);
        }
        if (Constants.ENCRYPTION_TLS.equalsIgnoreCase(encryption)) {
            properties.put("mail.smtp.starttls.enable", "true");
        }
        logger.debug("Result properties: {}", properties.toString());

        if (Strings.isNullOrEmpty(smtpUser)) {
            return Session.getInstance(properties);
        } else {
            return Session.getInstance(properties, new javax.mail.Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(smtpUser, smtpPassword);
                }
            });
        }
    }