public class EmailService {
    private static final String MAIL_SMTP_HOST = "mail.smtp.host";
    private static final String MAIL_SMTP_PORT = "mail.smtp.port";
    private static final String MAIL_DEBUG = "mail.debug";

    @Inject
    EmailConfig config;

    public void sendWithAttachment(InputStream inputStream, String subject, String fileName, InternetAddress... mailTo) throws MessagingException {
        Properties properties = new Properties();
        properties.setProperty(MAIL_SMTP_HOST, config.getSmtpHost());
        properties.setProperty(MAIL_SMTP_PORT, "" + config.getSmtpPort());
        properties.setProperty(MAIL_DEBUG, "" + config.isMailDebug());
        Session mailSession = Session.getDefaultInstance(properties);
        try {
            // формируем содержимое письма
            MimeMultipart mimeMultipart = new MimeMultipart();
            // тело сообщения
            MimeBodyPart mailBody = new MimeBodyPart();
            mailBody.setText("См. прикпленный файл", "UTF-8", "plain" /*MIME subtype*/);
            mimeMultipart.addBodyPart(mailBody);
            // прикрепленный файл
            MimeBodyPart mailAttach = new MimeBodyPart();
            DataHandler dataHandler = new DataHandler(new ByteArrayDataSource(inputStream, "application/octet-stream"));
            mailAttach.setDataHandler(dataHandler);
            mailAttach.setFileName(fileName);
            mimeMultipart.addBodyPart(mailAttach);
            // формируем сообщение
            MimeMessage mimeMessage = new MimeMessage(mailSession);
            mimeMessage.setFrom(config.getMailFrom());
            mimeMessage.setContent(mimeMultipart);
            mimeMessage.setSubject(subject);
            mimeMessage.setRecipients(Message.RecipientType.TO, mailTo);

            // TODO envelope - шифрование, подпись...

            // отправляем письмо
            Transport.send(mimeMessage);
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }
}