@Autowired
private JavaMailSenderImpl mailSender;

for (Email_Mess mess : emails) {
 MimeMessage message = mailSender.createMimeMessage();
 ... //set values from email_mess
 mailSender.send(message);
}

> host                        = smtp.office365.com
> port                        = 587
> mail.transport.protocol     = smtp
> mail.smtp.auth              = true
> mail.smtp.starttls.enable   = true
> mail.debug                  = true
> mail.smtp.connectiontimeout = 2000