Assume that you have the following operation:
void AddCustomer(Customer)
(i.e. a Customer object as input and no output)
Complying to WS-I BP 1.1 you are not allowed to define fault messages for one-way operations [1]. However, you may want to throw an exception in case, for example, the customer is a duplicate. How would you achieve this? Defining the operation as a request/response with an empty response signaling that the operation succeeded? Not that pretty in my opinion… Maybe you know another way? I mean: within a java/.net program you still want to be able to throw exceptions also for void-methods…
Example:
<operation name="AddCustomer">
<input message="tns:AddCustomerRequest"/>
<output message="tns:AddCustomerResponse"/>
<fault name="DuplicateCustomer" message="tns:DuplicateFault"/>
</operation>
where AddCustomerResponse would be an empty sequence.
According to the wsdl 1 specification there is no solution for this.