Hi E Robb,
I'm reading the same book, although I don't think I'm as far as you are yet.
AFAIK (and I'm willing to be corrected here), javax.persistence is for the
Java Persistence API - this is the API that can be used for storing entities in a Database. It's an API that has been derived for providers to then supply implementations to (e.g. Hibernate or TopLinks), and you can use it to get a consistent API regardless of the provider, for storing your Entities in a database.
However, if you are using WebServices, then this is the wrong API. Perhaps something like AXIS2/JAX-RPC/JAX-WS might be more useful if you are trying to get information from WebServices instead?
Hope that helps,
MG
28/06/06 - SCJP - 69%, 05/06/07 - SCWCD - 92%, 28/02/08 - IBM DB2 v9 Fundamentals (Exam 730) - 87%, 18/11/08 - IBM DB2 v9 DBA (Exam 731) - 89%, 26/02/11 - SCBCD - 88%