Error 415 Unsupported Media Type: POST not reaching REST if JSON, but it does if XML

Question

I am actually new to REST WS but really I don\'t get this 415 Unsupported Media Type.

I am testing my REST with Poster on Firefox and the GET

Answer 1

Don't return Strings in your methods but Customer objects it self and let JAXB take care of the de/serialization.