JIRA: https://jira.spring.io/browse/INT-2543 We may have a mail server host configured in the properties and the target session will resolve it properly from provided `javaMailProperties`. The same applies for `username` * Do not require `host` and `username`, when `javaMailProperties` is provided * Add additional factory methods into the `Mail` factory for Java DSL * Add Java DSL sample into the `mail.adoc`