If you are using the Client Framework and your proxy methods return something other than a ClientResponse, the default client error handling comes into play. Any response code that is greater than 399 will automatically cause a org.jboss.resteasy.client.ClientResponseFailure exception:

   @GET
   ClientResponse<String> get() // will throw an exception if you call getEntity()

   @GET
   MyObject get(); // will throw a ClientResponseFailure on response code > 399