JsonInclude.Include.NON_EMPTY does not replace deprecated WRITE_EMPTY_JSON_ARRAYS

In moving from Jackson 2.7.6 to 2.8.3, we are now getting compiler warnings with regards to our use of the SerializationFeature.WRITE_EMPTY_JSON_ARRAYS. From what I can tell, the recommendation is to replace this with JsonInclude.Include.NON_EMPTY.

Our code previously looked like this:

public static ObjectMapper getJacksonObjectMapper() {
    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
    mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
    mapper.configure(SerializationFeature.WRITE_EMPTY_JSON_ARRAYS, false);
    mapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
    return mapper;
}

and when serializing JSON, empty arrays are omitted.

If I comment out the deprecated WRITE_EMPTY_JSON_ARRAYS line, and write the exact same object, the JSON has empty array elements within it.

Here is a simple test case, just unzip and run mvn package and look at the test output and you will see something that looks like the following:

Running test.EmptyArraysTest

Printing object with WRITE_EMPTY_JSON_ARRAYS set to false:

{ “id” : “123” }

Printing object without WRITE_EMPTY_JSON_ARRAYS:

{ “id” : “123”, “databases” : [ ] }

What am I missing?
jackson-empty-arrays-test.zip

[cowtowncoder]

@rpatrick00 The problem here is that MyClass has override for @JsonInclude:

@JsonInclude(JsonInclude.Include.NON_NULL)

which will only suppress writing of nulls; since it is more specific than global defaults it will have precedence.

Another thing to note on replacement is that in addition to global inclusion default, and per-property annotation (that is, can put @JsonInclude on field/setter/getter), with 2.8 you can also specify type defaults:

        mapper.configOverride(Map.class)
            .setInclude(JsonInclude.Value.construct(JsonInclude.Include.NON_EMPTY, null));

which should then make all List<> valued properties default to excluding empty, as well as null, values.

[cowtowncoder]

Quick note here: if anyone wants to re-open the feature request, please do so at jackson-databind as Annotations package only deals with definition of annotations themselves and not any logic taken on them. If filing a new one (I’d rather do that than transfer this one), you can add reference this issue as background, but please summarize how “config overrides” is not workable solution.