Apache ServiceMix

Apache ServiceMix is an enterprise-class open-source distributed enterprise service bus (ESB).
Architecture.
It is based on the service-oriented architecture (SOA) model. It is a project of the Apache Software Foundation and was built on the semantics and application programming interfaces of the Java Business Integration (JBI) specification JSR 208. The software is distributed under the Apache License. ServiceMix fully supports the OSGi framework. ServiceMix is lightweight and easily embeddable, has integrated Spring Framework support and can be run at the edge of the network (inside a client or server), as a standalone ESB provider or as a service within another ESB. ServiceMix is compatible with Java SE or a Java EE application server. ServiceMix uses ActiveMQ to provide remoting, clustering, reliability and distributed failover. The basic frameworks used by ServiceMix are Spring and XBean.
ServiceMix is composed the latest versions of Apache ActiveMQ, Apache Camel, Apache CXF, and Apache Karaf. It was accepted as an official Apache project by the ASF Board of Directors on September 19, 2007.