Jackson not serializing property

Question

I have the following two enums

public enum Action {
    ACTION1,
    ACTION2,
    ACTION3;
}

public enum EntityType {
    ENTITYTYPE1,
    ENTITYTYPE2;
}

and the following class

public class EntityIdentityDto implements MetaData {
    private String id;
    private EntityType entityType;
    private Action action;
    private Map<String, Object> properties = new HashMap();

    public String getId() {
        return this.id;
    }

    public EntityType getEntityType() {
        return this.entityType;
    }

    public Action getAction() {
        return this.action;
    }

    public Map<String, Object> getProperties() {
        return this.properties;
    }

    public void setId(String id) {
        this.id = id;
    }

    public void setEntityType(EntityType entityType) {
          this.entityType = entityType;
    }

    public void setAction(Action action) {
        this.action = action;
    }

    public void setProperties(Map<String, Object> properties) {
        this.properties = properties;
    }

    public EntityIdentityDto() {
    }

}

When using Jackson 2.9.8 to serialize into Json as per below

public class TestMe {
    public static void main(String[] args) throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();
        EntityIdentityDto entityIdentityDto = new EntityIdentityDto();
        entityIdentityDto.setEntityType(EntityType.ENTITYTYPE1);
        entityIdentityDto.setAction(Action.ACTION1);
        entityIdentityDto.setId("OOO");
        String out = objectMapper.writeValueAsString(entityIdentityDto);
        System.out.println(out);
    }
}

The output is

{"id":"OOO","action":"ACTION1","properties":{}}

I am expecting to so the entityType field serialized as well but this is missing. This is what I expect to see

{"id":"OOO","entityType": "ENTITYTYPE1", "action":"ACTION1","properties":{}}

If instead of Jackson I use Gson as per below

public class TestMe {
    public static void main(String[] args) throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();
        EntityIdentityDto entityIdentityDto = new EntityIdentityDto();
        entityIdentityDto.setEntityType(EntityType.SYSTEM);
        entityIdentityDto.setAction(Action.SYNC);
        entityIdentityDto.setId("OOO");
        System.out.println(new Gson().toJson(entityIdentityDto));
    }
}

The output is as expected

{"id":"OOO","entityType":"ENTITYTYPE1","action":"ACTION1","properties":{}}

Why is the entityType field missing in the Json generated using Jackson ? It is interesting that action gets serialized but entityType does not even though they are structurally identical and used identically in the EntityIdentityDto

For me, Jackson also produced the same output. Which version of Jackson are you using? I tried it on version `2.10.0.pr3`. Probably you are missing getters? — Mushif Ali Nawaz, Oct 05 '19 at 18:45
I would guess this is an environment/configuration/forgot-to-recompile-all-classes type error — flakes, Oct 05 '19 at 18:47
I would guess this is also environment/configuration/forgot-to-recompile-all-classes type issue but can confirm I have cleaned the environment, rebuilt using both the IDE and gradle with the same result. — Khetho Mtembo, Oct 05 '19 at 19:04
@KhethoMtembo, how `ObjectMapper` configuration looks like? Do you use any modules, custom serialisers, filters, etc.? — Michał Ziober, Oct 05 '19 at 19:19

Michał Ziober · Answer 1 · 2019-10-05T18:57:19.450

0

Probably you do not have getter for entityType property. Add getter or use setVisibility method:

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);

See also:

edited Oct 05 '19 at 18:57

answered Oct 05 '19 at 18:50

Michał Ziober

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I use lombok to generate the getters and setters. I have updated the question to show the generated code used at runtime. – Khetho Mtembo Oct 05 '19 at 19:00
@KhethoMtembo, How it works with `setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY)`? The output is the same? – Michał Ziober Oct 05 '19 at 19:16
The entityType field still does not get serialized with visibility set to ANY – Khetho Mtembo Oct 05 '19 at 19:29

score 0 · Accepted Answer · answered Oct 05 '19 at 21:49

The issue was with my EntityIdentityDto class which implements the following interface

public interface MetaData {
    String getId();
    Map<String, Object> getProperties();
    void setProperties(Map<String, Object> properties);

    @JsonIgnore
    EntityType getEntityType();
}

The JsonIgnore at the interface level is the reason why it was not being serialized. After dropping the JsonIgnore all works as expected now.

Jackson not serializing property

2 Answers2