I am using Java enums as request parameters with JAX-WS style web services which are generated with the jwsc ant task. I am finding that if an invalid value is passed for a given enum parameter, the Java class upon which the service is built receives a null value for that parameter. There is no indication to either the client or the server class that a parsing error occurred. If a parameter is optional, there is no way to differentiate between that parameter being omitted and an invalid value being specified. Debugging the server code, it appears that JAXB throws an exception during parsing, but the jax-ws layer eats the exception and continues on.
Is there any way to intercept this failure and return a meaningful error to the caller?