A BPEL application can generate and receive fault messages. The throw activity has three elements: its name, the name of the fault, and the fault variable. The fault thrown by a throw activity is internal to BPEL. You cannot use a throw activity on an asynchronous process to communicate with a client. Throw activity syntax includes the throw name, fault name, and fault variable:

<throw name="delay" faultName="nsPrefix:fault-1" faultVariable="fVar"/>