Proteus is a framework for creating messaging applications, and a message broker built upon that framework.

Proteus has adapters that allow databases, message queues, ftp servers, email and other message sources and sinks to be addressed in a simple, uniform fashion. It differs in approach from most other toolkits in supporting both centralized and point to point implementations with a minimal footprint.

Features
written in 100% Java for portability (WIN32,POSIX and even OS/390 MVS)
convenient for Java developers to use and extend (no new languages or complex commands to learn)
simple and elegant model
minimal footprint and simple installation
all components configured by xml
message broker with routing and transformation capabilities
support for XSLT and custom Java transformations
adapters for JMS, databases (any JDBC compliant), native MQSeries, FTP, Tibco Rendezvous
adapters for email, flat files, WebMethods coming soon