JacksonProviderProxy writing out null values in json output
jackson, json
Solution
Different options are available for suppressing serialization of properties with null values, depending on the version of Jackson in use, and whether the `ObjectMapper` can be directly configured.
With Jackson 1.1+, with direct access to configure the `ObjectMapper`, you could just call `setSerializationInclusion`(`Include.NON_NULL`).
Alternatively, you could annotate the (class) type that has the properties, for which null properties serialization is to be suppressed, with `@JsonSerialize`(`include``=``Inclusion.NON_NULL`).
With Jackson 2+, instead of the `@JsonSerialize` annotation, use `@JsonInclude`(`Include.NON_NULL`).
Problem
I have a simple POJO class that extends another simple POJO class. I am using the `com.sun.jersey.json.impl.provider.entity.JacksonProviderProxy` to marshall the properties in these POJO classes to JSON. However, when I set some of the properties to the POJO as `null`, then it outputs those properties as the string `null` instead of not outputting it at all. for eg. ``` { Person: [{ "firstName":"John" "lastName":"null" }] } ``` instead of: for eg. ``` { Person: [{ "firstName":"John" }] } ```