This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Any SOAP fault will be in the body of the SOAP message if an error has occurred, not associated with a message context.
Note that I assume you are talking about an object implementing the interface javax.xml.ws.handler.MessageContext. Such an object is only accessible in handlers, I recall.