Axis is essentially Apache SOAP 3.0. It is a from-scratch rewrite, designed around a streaming model (using SAX internally rather than DOM). The intention is to create a more modular, more flexible, and higher-performing SOAP implementation (relative to Apache SOAP 2.0).
Little additional stuff here. "axis" in the context of xslt & xpath makes xpath expressions more powerful. This is how. With the use of axes, we can refer to different portions of an XML tree for any given node, e.g., children, ancestors, descendants, siblings, etc. Please look at this tutorial link that covers this topic - The tutorial on XPath from O'Reilly is - http://www.oreilly.com/catalog/xmlnut/chapter/ch09.html Please look at the section "Unabbreviated Location Paths"