Deserialization With @Jsonsubtypes for No Value - Missing Property Error

Deserialization with @JsonSubTypes for no value - missing property error

I've also encountered this issue, and could not find an elegant solution using the mechanisms provided by Jackson (custom BeanDeserializer, BeanDeserializerModifier, etc.).

It looks like a bug in the way external type IDs are handled. I worked around it by:

1. deserializing the JSON tring to a JsonNode;
2. manually inserting a null node if the required property is not present;
3. mapping the JsonNode to my desired value type.

My code looks something like the following:

public <T> T decode(String json, Class<T> type) throws IOException {
    JsonNode jsonNode = mapper.readTree(json);

    if (jsonNode.isObject() && (jsonNode.get("payload") == null  || jsonNode.get("payload").size() == 0)) {
        ObjectNode objectNode = (ObjectNode) jsonNode;
        objectNode.putNull("payload");
    }

    return mapper.treeToValue(jsonNode, type);
}

Missing property 'type' while De/Serialization of Map the contains mixed subtype - polymorphism

Instead of:
mapper.writeValue(sw, animals);
use
mapper.writerFor(new TypeReference<Map<String, ? extends Animal>>() {}).writeValue(sw, animals);

And instead of:
mapper.readValue(animlasStr, new TypeReference<Map<String, Animal>>() {});
use:
mapper.readValue(animlasStr, new TypeReference<Map<String, ? extends Animal>>() {});

with empty constructors in all the classes

How to use dynamic deserialization on a property using JsonSubTypes?

You need to use JsonTypeInfo.As.EXTERNAL_PROPERTY. From documentation:

Inclusion mechanism similar to PROPERTY, except that property is
included one-level higher in hierarchy, i.e. as sibling property at
same level as JSON Object to type. Note that this choice can only be
used for properties, not for types (classes). Trying to use it for
classes will result in inclusion strategy of basic PROPERTY instead.

See also:

• Jackson JsonTypeInfo.As.EXTERNAL_PROPERTY doesn't work as expected

Polymorphic deserialization Jackson issue

You can see this post I think you'll find what you want :
Jackson JSON Polymorphism

PS : be carreful, you sometime have "_type" and sometime "type".

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