When you generate a JAX-WS client from a locally deployed service, the URL for the endpoint and the WSDL are hardcoded into the generated client code. If you redeploy the service elsewhere (i.e. moving from a local development environment to a test or production environment), then you could regenerate against the new URL for the service, but the JAX-WS api does allow you to programmatically specify the endpoint and wsdl locations.
From this post, the key is to use the BindingProvider to specify a new value for BindingProvider.ENDPOINT_ADDRESS_PROPERTY:
BindingProvider bp = (BindingProvider)port;
bp.getRequestContext().put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY, "http://your_url/ws/sample");
By itself though, this gave me an additional exception as it appears the client it still attempting to locate the WSDL. To work around this, you can also pass the new WSDL url location when you instantiate the generated client (this is discussed here). Before using the BindingProvider snippet above, pass the updated urls into the client like this:
EndpointService service = new EndpointService(
new URL("http://your-url-to-endpoint/Endpoint?wsdl"),
new QName("http://namespace-of-endpoint-from-wsdl/",
"EndpointService"));
SpotCollectorEndpoint endpoint = service.getSpotCollectorEndpointPort();