An implementation may thow a SOAPFaultException

public void throwSoapFaultException()
{
SOAPFactory factory = SOAPFactory.newInstance();
SOAPFault fault = factory.createFault("this is a fault string!", new QName("http://foo", "FooCode"));
fault.setFaultActor("mr.actor");
fault.addDetail().addChildElement("test");
throw new SOAPFaultException(fault);
}

or an application specific user exception

public void throwApplicationException() throws UserException
{
throw new UserException("validation", 123, "Some validation error");
}