I don't think think is possible because the framework will return immediately on connecting to a @Oneway service. I'm not sure if schema validation is the right approach, but perhaps bean validation is something that might work instead? http://cxf.apache.org/docs/validationfeature.html#ValidationFeature-CommonBeanValidation1.1Interceptors
Mustafa, thank you for advice. I'll try to use bean validation.
The main reason why I want to validate inbound messages against schema is that JAXB silently sets null to (for example) Integer field if corresponding XML-field contains invalid data (not a number).