The JSON to POJO mapping uses a mechanism of the entity provider of the JAX-RS specifications. Therefore, exceptions thrown during the JSON to POJO mapping is handled in the same way as the exceptions thrown during any other mapping. For details on how exceptions are handled during mapping, see 17.1.3 Return value, and for mapping on servers and clients, see 25.15.2 Combination of Java types and MIME media types available for an HTTP response entity.