title: ExceptionMapper not invoked if receiving invalid JSon
body: <p>I am using Jersey 2.5.1 with Jackson 2.2. for building JSON Rest web services. I kind of got it up and running also with 2 ExceptionMappers but for a "not-json" request the application is not throwing any exception!</p>
  
  <ol>
  <li><p>ExceptionMapper 
  Will be invoked if e.g. a NullPointerException is thrown</p></li>
  <li><p>ExceptionMapper
  Will be invoked if there s a problem with the JSon Mapping</p></li>
  </ol>
  
  <p>My Problem:
  1. Request Body: {} works
  2. Request Body: {} with an application side NullPointer invoked the first exception mapper
  3. Request Body: "jibberish" does not invoke anything (not caught by any ExceptionMapper) cause no Exception is thrown. Unfortunately the response body is sth like : Unrecognized field "xxx" (class com.sample.MyDto), not marked as ignorable (9 known properties...
  ....> but I want to customize the error msg since I am always returning a JSon object.</p>