Sardine is a next generation WebDAV client for Java. It is intended to be simple to use and does not implement the full WebDAV client spec. Instead, the goal is to provide methods for most use case scenarios when working with a WebDAV server. The code needs to run as fast as possible and use the latest released Apache HttpComponents.
exJello is a JavaMail provider that connects to a Microsoft Exchange server (actually, it uses the WebDAV interface exposed by Outlook Web Access). It is designed as a drop-in replacement for the standard POP3 and SMTP providers. This allows you to send and receive messages through your Exchange server in situations where a POP3/SMTP interface is not available (through a restrictive firewall, for example, or if your administrator simply does not provide a POP3 or SMTP gateway).