android - No Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator

Question

I am trying to consume an API using Retrofit and Jackson to deserialize. I am getting the onFailure error No Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator.

Answer 1

Reason: This error occurs because jackson library doesn't know how to create your model which doesn't have empty constructor and the model contains constructor with parameters which didn't annotated its parameters with @JsonProperty("field_name"). By default java compiler creates empty constructor if you didn't add constructor to your class.

Solution: Add empty constructor to your model or annotate constructor parameters with @JsonProperty("field_name")

If you use kotlin data class then also can annotate with @JsonProperty("field_name") or register jackson module kotlin to ObjectMapper.

You can create your models using http://www.jsonschema2pojo.org/.