While I was working on preparing slides for my session on TmaxDay 2006 (http://www.tmax.co.kr/tmaxday/), I came up with some idea of grouping and classifying Java web services technologies:

Java Web Services 1.0 (adopted by J2EE 1.4)

JAXP 1.2
SAAJ 1.2
JAX-RPC 1.1
(Optional) EWS (JSR 109) 1.1

Java Web Services 2.0 (adopted by Java EE 5 and Java SE 6)

JAXP 1.3 + StAX 1.0 (= JAXP 1.4)
SAAJ 1.3
JAXB 2.0 + JAX-WS 2.0 (JSR 181 included)
(Optional) EWS 1.2

Instead of calling each Java XML and Web Services technology for a certain level or time of Java EE, we can simply say "JWS (pronounced "J Wiz") 1.0" for the former set and "JWS 2.0" for the latter set. Actually this idea was inspired by Sun's i-Stack that emcompasses JAXB, JAX-RPC, JAX-WS, and so on.

Yeah, I also have to admit that JWS 2.0 is another wave of "2.0" just like Web 2.0 :-)