Jackson Serialization Problems - serialization

Question

I am having some trouble serializing/deserializing my classes below.
My Data class holds a list of other classes.
When I call the serialize/deserialize methods in the Data class, I get the following error:
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of com.amazon.rancor.storage.types.ChildData: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
The error comes from the deserialize method. But I also believe the serialization is not working properly. This is what the serialized Data object looks like:
{childData:[{zipCode:{present:true},countryCode:"US"}]
The Optional field is not being serialized properly even though I have set the objectMapper.registerModule(new Jdk8Module()); field
I can't seem to figure out what I am doing wrong. Maybe I need to change something in ChildData and ChildDataV2 class. But I am not sure what.
Any pointers would be appreciated!
public class Data {
private List<ChildData> childData;
private List<ChildDataV2> childDataV2;
private static ObjectMapper objectMapper;
static {
objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapper.registerModule(new Jdk8Module());
}
public Data() { }
#JsonCreator
public Data(#JsonProperty("childData") final List<ChildData> childData,
#JsonProperty("childDataV2") final List<ChildDataV2> childDataV2) {
this.childData = childData;
this.childDataV2 = childDataV2;
}
public List<ChildData> getChildData() {
return childData;
}
public void setChildData(final List<ChildData> childData) {
this.childData = childData;
}
public List<ChildDataV2> getChildDataV2() {
return childDataV2;
}
public void setChildDataV2(final List<ChildDataV2> childDataV2) {
this.childDataV2 = childDataV2;
}
public String serialize() {
try {
return objectMapper.writeValueAsString(this);
} catch (JsonProcessingException e) {
throw new RuntimeException("Failed to serialize. Data: " + this, e);
}
}
public Data deSerialize(final String data) {
try {
return objectMapper.readValue(data, Data.class);
} catch (IOException e) {
throw new RuntimeException("Failed to deserialize. Data" + data, e);
}
}
}
public class ChildData {
private final String countryCode;
private final Optional<String> zipCode;
public ChildData(final String countryCode, final Optional<String> zipCode) {
this.countryCode = countryCode;
this.zipCode = zipCode;
}
public Optional<String> getZipCode() {
return zipCode;
}
public String getCountryCode() {
return countryCode;
}
}
public class ChildDataV2 extends ChildData {
private final Object struct;
public ChildDataV2(final String cc, final Optional<String> postalCode,
final Object struct) {
super(cc, postalcode);
this.struct = struct;
}
}

Answer 1

The exception is quite clear right? You need to add a default constructor for ChildData or annotate the existing constructor like this:
#JsonCreator
public ChildData(#JsonProperty("countryCode") String countryCode, #JsonProperty("zipCode") Optional<String> zipCode) {
this.countryCode = countryCode;
this.zipCode = zipCode;
}