Q1:SOAP uses HTTP as a transport, so does this mean that it is restricted to synchronous interaction?
A1: Any transport can be used for a SOAP message as long as someone creates a binding for it. SOAP bindings have been defined for SMTP, and such bindings can be created for any other transport mechanism, such as FTP or MQSeries, regardless of whether such mechanisms are synchronous or asynchronous.

Also, although HTTP is inherently synchronous, you can use it to pass XML documents that consist of business “messages” and that form part of a workflow. If the sender of the message is also capable of receiving such messages, it may receive a response of some form at some future point in time. This uses two synchronous interactions to create asynchronous ...

Get Sams Teach Yourself J2EE™ in 21 Days, Second Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.