When I was talking about Web application, I was thinking of JSP/Servlets specification.
But, let's talk about Web Services applications.
First we're not involved directly in JSR 156 (JCP and Open Source do not mix very well...) but we're interested to see where it is going.
We believe that transactions processing with be a main issue when Web Services become more widely used.
ACID transaction are not adapted to Web Services (they're short-lived and live in a trusted domain)
So I don't think than ACID transactions will be a lot used for Web Services but instead WS will use Long Running Activities (or Business Transactions).
As for our position wrt specifications (a similar discussion has been held on JOTM mailing list): the choice is now between WS-CAF and WS-T (almost all companies behind BTP are now behind either WS-CAF or WS-T). We do have an implementation of BTP but only ACID transactions are supported.
Companies behind WS-CAF have expressed their desire to give it to a open standards body (W3C or OASIS) and to allow Open Source implementation of it.
WS-T is the property of IBM, Microsoft and BEA and
it seems that an Open Source implementation of it is not legally possible.
So our choice would be WS-CAF (*when* it is submitted to a standards body).
hope it clarifies JOTM position,