Apache Axis2 is a core engine for Web services. It is a complete re-design and re-write of the widely used Apache Axis SOAP stack. Implementations of Axis2 are available in Java and C.
Axis2 not only provides the capability to add Web services interfaces to Web applications, but can also function as a standalone server application.
Axis2 has support for REST by just removing the SOAP headers both on the client and on the server.
Axis2 has support for Spring Framework.
Reference:
http://en.wikipedia.org/wiki/Apache_Axis2
