How to deserialize response json with Spring RestTemplate using Builder Pattern and @JsonDeserialize

Question

How do you configure RESTTemplate to deserialize the response Json using Jackson's @JsonDeserialize?

My domain classes based on Builder Pattern and jackson's @JsonDeserialize marshall and unmarshall fine in unit tests. However, when used in conjunction with Spring's RESTTemplate (Spring 3.1) it fails.

Domain class:

@JsonDeserialize(builder = Policy.Builder.class)
public final class Policy implements Comparable, Serializable {

    // immutable attributes

    private Policy(Builder builder) {
        ...
    }

    @JsonIgnoreProperties(ignoreUnknown = true)
    public static class Builder {

        /// withXXX methods 

        public Policy build() {
            return new Policy(this);
        }
    }
}

Spring RESTTemplate code in Unit test:

Policy policy = new Policy.Builder().withXXX()...build();
restTemplate.postForObject("http://localhost:8080/policies/policy.json", policy, String.class);

Error in RestTemplate#doExecute() - line 436:

org.springframework.web.client.HttpServerErrorException: 500 Could not instantiate bean    
class [xxx.domain.Policy]: No default constructor found; nested exception is 
java.lang.NoSuchMethodException: xxx.domain.Policy.()

Answer 1

if a constructor is already defined you need to include the default constructor.