Spring's generic mail infrastructure.
Concrete implementations are provided in the subpackages.
||This is a common interface for mail messages, allowing a user to set key
values required in assembling a mail message, without needing to know if
the underlying message is a simple text message or a more sophisticated
||This interface defines a strategy for sending simple mails.
||Models a simple mail message, including data such as the from, to, cc, subject, and text fields.