One thing that plagues other smaller libraries is the lack of true RFC compliance. Though fine for simple mails, this becomes a testing nightmare if for example you need to send an HTML mail (with text fall-back?) using both attachment and embedded images.
The problem becomes evident when testing the mail in various e-mail clients (desktop, web based, mobile) by the fact that the e-mails will be displayed completely inconsistent and sporadic. Symptoms include:
<name>
part in <name> adres@domain.com
)
The research has been done and Simple Java Mail is RFC compliant for simple to complex mails. Furthermore, it has been tested in a range of known clients such as Outlook, Thunderbird, Gmail, Hotmail, Android, iPhone etc.
Simple Java Mail is in two ways RFC (MIME) compliant: