1. Can someone please point me to the specs that are relelvant to this exam? For example in the SCJP exam, there is one document for the language specification. For SCBCD, there are three documents from Oracle: a document called Simple, one called Core, and JPA. Where are the specs for this JWSD exam ?
2. Can anyone comment from experience re the worthiness of these mock exam providers : examsim.com, ucertify.com, whizlabs.com ?
I've used practice exams from enthuware for SCJP and SCBCD, and they are great. But they do not have SCDJWS.
I will only try to answer your first question, since I know little about the mock exams:
There is no single specification document to read, but if you want to get started, I would recommend taking a look at the XML specifications, the WSDL specification and the WS-I Basic Profile.
Just reading the specification documents are quite tedious, so I recommend alternating with some programming exercises or some other, more practical, work.