mail:
    host: smtp.gmail.com
    port: 587
    username: **********@gmail.com
    password: ****************
    protocol: smtp
    tls: true
    properties.mail.smtp:
            auth: true
            starttls.enable: true
            ssl.trust: smtp.gmail.com

@Async
public void sendEmail(String to, String subject, String content, boolean isMultipart, boolean isHtml) {
    log.debug("Send e-mail[multipart '{}' and html '{}'] to '{}' with subject '{}' and content={}",
        isMultipart, isHtml, to, subject, content);

    // Prepare message using a Spring helper
    MimeMessage mimeMessage = javaMailSender.createMimeMessage();
    try {
        MimeMessageHelper message = new MimeMessageHelper(mimeMessage, isMultipart, CharEncoding.UTF_8);
        message.setTo(to);
        message.setFrom(jHipsterProperties.getMail().getFrom());
        message.setSubject(subject);
        message.setText(content, isHtml);
        javaMailSender.send(mimeMessage);
        log.debug("Sent e-mail to User '{}'", to);
    } catch (Exception e) {
        log.warn("E-mail could not be sent to user '{}'", to, e);
    }
}