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

Try below models. I used http://www.jsonschema2pojo.org/ to create these models.

StationResponse.java

import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"data"
})
public class StationResponse {

@JsonProperty("data")
private Data data;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

@JsonProperty("data")
public Data getData() {
return data;
}

@JsonProperty("data")
public void setData(Data data) {
this.data = data;
}

@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}

Data.java

import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"repsol_id",
"name",
"latitude",
"longitude",
"address",
"post_code",
"location",
"service_store",
"service_mechanical_workshop",
"service_restaurant",
"service_wash"
})
public class Data {

@JsonProperty("repsol_id")
private String repsolId;
@JsonProperty("name")
private String name;
@JsonProperty("latitude")
private String latitude;
@JsonProperty("longitude")
private String longitude;
@JsonProperty("address")
private String address;
@JsonProperty("post_code")
private String postCode;
@JsonProperty("location")
private String location;
@JsonProperty("service_store")
private Integer serviceStore;
@JsonProperty("service_mechanical_workshop")
private Integer serviceMechanicalWorkshop;
@JsonProperty("service_restaurant")
private Integer serviceRestaurant;
@JsonProperty("service_wash")
private Integer serviceWash;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

@JsonProperty("repsol_id")
public String getRepsolId() {
return repsolId;
}

@JsonProperty("repsol_id")
public void setRepsolId(String repsolId) {
this.repsolId = repsolId;
}

@JsonProperty("name")
public String getName() {
return name;
}

@JsonProperty("name")
public void setName(String name) {
this.name = name;
}

@JsonProperty("latitude")
public String getLatitude() {
return latitude;
}

@JsonProperty("latitude")
public void setLatitude(String latitude) {
this.latitude = latitude;
}

@JsonProperty("longitude")
public String getLongitude() {
return longitude;
}

@JsonProperty("longitude")
public void setLongitude(String longitude) {
this.longitude = longitude;
}

@JsonProperty("address")
public String getAddress() {
return address;
}

@JsonProperty("address")
public void setAddress(String address) {
this.address = address;
}

@JsonProperty("post_code")
public String getPostCode() {
return postCode;
}

@JsonProperty("post_code")
public void setPostCode(String postCode) {
this.postCode = postCode;
}

@JsonProperty("location")
public String getLocation() {
return location;
}

@JsonProperty("location")
public void setLocation(String location) {
this.location = location;
}

@JsonProperty("service_store")
public Integer getServiceStore() {
return serviceStore;
}

@JsonProperty("service_store")
public void setServiceStore(Integer serviceStore) {
this.serviceStore = serviceStore;
}

@JsonProperty("service_mechanical_workshop")
public Integer getServiceMechanicalWorkshop() {
return serviceMechanicalWorkshop;
}

@JsonProperty("service_mechanical_workshop")
public void setServiceMechanicalWorkshop(Integer serviceMechanicalWorkshop) {
this.serviceMechanicalWorkshop = serviceMechanicalWorkshop;
}

@JsonProperty("service_restaurant")
public Integer getServiceRestaurant() {
return serviceRestaurant;
}

@JsonProperty("service_restaurant")
public void setServiceRestaurant(Integer serviceRestaurant) {
this.serviceRestaurant = serviceRestaurant;
}

@JsonProperty("service_wash")
public Integer getServiceWash() {
return serviceWash;
}

@JsonProperty("service_wash")
public void setServiceWash(Integer serviceWash) {
this.serviceWash = serviceWash;
}

@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}

You need to use jackson-kotlin-module to deserialize to data classes. See here for details.

The error message above is what Jackson gives you if you try to deserialize some value into a data class when that module isn’t enabled or, even if it is, when the ObjectMapper it uses doesn’t have the KotlinModule registered. For example, take this code:

data class TestDataClass (val foo: String)

val jsonString = """{ "foo": "bar" }"""
val deserializedValue = ObjectMapper().readerFor(TestDataClass::class.java).readValue<TestDataClass>(jsonString)

This will fail with the following error:

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `test.SerializationTests$TestDataClass` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator)

If you change the code above and replace ObjectMapper with jacksonObjectMapper (which simply returns a normal ObjectMapper with the KotlinModule registered), it works. i.e.

val deserializedValue = jacksonObjectMapper().readerFor(TestDataClass::class.java).readValue<TestDataClass>(jsonString)

I’m not sure about the Android side of things, but it looks like you’ll need to get the system to use the jacksonObjectMapper to do the deserialization.

I got here searching for this error:

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

Nothing to do with Retrofit but if you are using Jackson this error got solved by adding a default constructor to the class throwing the error.
More here: https://www.baeldung.com/jackson-exception

If you’re using Lombok on a POJO model, make sure you have these annotations:

@Getter
@Builder
@NoArgsConstructor
@AllArgsConstructor

It could vary, but make sure @Getter and especially @NoArgsConstructor.

I know this is an old post, but for anyone using Retrofit, this can be useful useful.

If you are using Retrofit + Jackson + Kotlin + Data classes, you need:

1. add implement group: 'com.fasterxml.jackson.module', name: 'jackson-module-kotlin', version: '2.7.1-2' to your dependencies, so that Jackson can de-serialize into Data classes
2. When building retrofit, pass the Kotlin Jackson Mapper, so that Retrofit uses the correct mapper, ex:

    val jsonMapper = com.fasterxml.jackson.module.kotlin.jacksonObjectMapper()

    val retrofit = Retrofit.Builder()
          ...
          .addConverterFactory(JacksonConverterFactory.create(jsonMapper))
          .build()

Note: If Retrofit is not being used, @Jayson Minard has a more general approach answer.

I had a similar issue (using Jackson, lombok, gradle) and a POJO without no args constructor – the solution was to add

lombok.anyConstructor.addConstructorProperties=true

to the lombok.config file

I’m using rescu with Kotlin and resolved it by using @ConstructorProperties

    data class MyResponse @ConstructorProperties("message", "count") constructor(
        val message: String,
        val count: Int
    )

Jackson uses @ConstructorProperties. This should fix Lombok @Data as well.

As the error mentioned the class does not have a default constructor.

Adding @NoArgsConstructor to the entity class should fix it.

I had the same symptoms the other day while using JsonCreator and JsonProperty but I got the same exact error message. In my case it turned out the json had a primitive type boolean, whereas my constructor awaited the wrapper class Boolean. So the framework was not able to find a suitable constructor.

If you are using Unirest as the http library, using the GsonObjectMapper instead of the JacksonObjectMapper will also work.

<!-- https://mvnrepository.com/artifact/com.konghq/unirest-object-mappers-gson -->
<dependency>
    <groupId>com.konghq</groupId>
    <artifactId>unirest-object-mappers-gson</artifactId>
    <version>2.3.17</version>
</dependency>

Unirest.config().objectMapper = GsonObjectMapper()

When you are using Lombok builder you will get the above error.

 @JsonDeserialize(builder = StationResponse.StationResponseBuilder.class)
 public class StationResponse{
   //define required properties 
 }     

 @JsonIgnoreProperties(ignoreUnknown = true)
 @JsonPOJOBuilder(withPrefix = "")
 public static class StationResponseBuilder {}

Reference : https://projectlombok.org/features/Builder With Jackson

I could resolve this problem in Kotlin with help of @JacksonProperty annotation. Usage example for above case would be:

import com.fasterxml.jackson.annotation.JsonProperty
...
data class Station(
     @JacksonProperty("repsol_id") val repsol_id: String,
     @JacksonProperty("name") val name: String,
...