Need help to deserialize generic type

[AlwaysNoobCoder]

I have a custom deserializer:

public class SelectiveUpdateVODeserializer extends JsonDeserializer<SelectiveUpdateVO<?>> implements ContextualDeserializer{

	private JavaType entityType;

	public SelectiveUpdateVODeserializer() {
		
	}

	@Override
	public SelectiveUpdateVO<?> deserialize(JsonParser jp, DeserializationContext ctxt)
			throws IOException, JsonProcessingException {
		System.out.println("---- entity type:" + entityType.getRawClass().getName());
		JsonNode node = jp.getCodec().readTree(jp);
		SelectiveUpdateVO<Object> selectiveUpdateVO = new SelectiveUpdateVO<>();
		node.fieldNames().forEachRemaining(pn -> {
			System.out.println("-------- property:" + pn);
			selectiveUpdateVO.include(pn);
		});
		Object entity = jp.getCodec().treeToValue(node, entityType.getRawClass());
		selectiveUpdateVO.setEntity(entity);
		return selectiveUpdateVO;
	}

	@Override
	public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property)
			throws JsonMappingException {
		System.out.println("---- createContextual with BeanProperty:" + property);
		JavaType wrapperType = property.getType();
                JavaType valueType = wrapperType.containedType(0);
                SelectiveUpdateVODeserializer deserializer = new SelectiveUpdateVODeserializer();
                deserializer.entityType = valueType;
                return deserializer;
	}

}

but when trying to deserialize some json like below:

{
    "entities": [
        {"id": "3e07248e-23ab-4d5f-a619-59077a6fa075", "email": "[email protected]"}
    ]
}

exception happens:

---- createContextual with BeanProperty:[property 'entities']
---- entity type:fwx.sea.api.model.SelectiveUpdateVO
-------- property:id
-------- property:email
---- createContextual with BeanProperty:null
2024-01-31T11:15:21.553+08:00 ERROR 65379 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[.[dispatcherServlet]      : Servlet.service() for servlet [dispatcherServlet] in context with path [/pus] threw exception

com.fasterxml.jackson.databind.JsonMappingException: Cannot invoke "com.fasterxml.jackson.databind.BeanProperty.getType()" because "property" is null (through reference chain: fwx.sea.api.model.SEAUpdateRequest["entities"]->java.util.ArrayList[0])
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:402) ~[jackson-databind-2.15.3.jar:2.15.3]
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:373) ~[jackson-databind-2.15.3.jar:2.15.3]
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer._deserializeFromArray(CollectionDeserializer.java:375) ~[jackson-databind-2.15.3.jar:2.15.3]
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:244) ~[jackson-databind-2.15.3.jar:2.15.3]
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:28) ~[jackson-databind-2.15.3.jar:2.15.3]
	at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129) ~[jackson-databind-2.15.3.jar:2.15.3]

why createContextual get called twice ? and why the BeanProperty is null, can some jackson experts help me to understand this ?

[AlwaysNoobCoder]

sorry for the noise, my bad.