UltraESB is the first [and still the only] Open Source Enterprise Service Bus (ESB) to utilize Zero-copy proxying with Memory Mapped files and Java Non-Blocking IO for extreme performance!
Apache CXF is an open source services framework. CXF helps you build and develop services using frontend programming APIs, like JAX-WS. These services can speak a variety of protocols such as SOAP, XML/HTTP, RESTful HTTP, or CORBA and work over a variety of transports such as HTTP, JMS or JBI.