Caucho Hessian
\"Hessian is a lightweight, self-describing binary RPC protocol\"
The Hessian binary web service protocol makes web services usable without requiring a large framework, and without learning yet another alphabet soup of protocols. Because it is a binary protocol, it is well-suited to sending binary data without any need to extend the protocol with attachments.
(追記) (追記ここまで)
License
Apache Software License