Axis of Apache

Java Web Services Technology
http://wiki.apache.org/ws/FrontPage/Axis

Axis uses SOAP protocol (Simple Object Access) for web services. It's a kind of XML-RPC.

WSDL is a specification to describe a web service (series of messages travelling between two endpoints). It is independent of the underlying protocol (e.g. SOAP).

In Axis, there is a java program, WSDL2Java, which generates client bindings for web service, described by WSDL. For .NET there is a corresponding program, wsdl.exe. Client-side Axis is built using JAX-RPC specification, a "key technology for web services integration".