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Deserialize json with polymorphic recursion using Jackson

I am trying to deserialize an object which has polymorphic recursion on a Map value. The first level always deserialize to the correct type, but the recursions are deserialized as LinkedHashMap.
Code:
public class Rule {
private String ruleName;
private List<Variable> variables;
}
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
#JsonSubTypes({
#Type(value = ListVariable.class, name = "ListVariable"),
#Type(value = MapVariable.class, name = "MapVariable")
})
public abstract class Variable<T> {
private String name;
private T value;
}
public class ListVariable extends Variable<List<Object>> {
}
public class MapVariable extends Variable<Map<String, Object>> {
private String input;
private Object defaultValue;
}
Json with multiple levels:
{
"ruleName" : "xyz",
"variables" : [ {
"type" : "MapVariable",
"name" : "multi_level_map",
"input" : "listing_country",
"defaultValue" : "Unknown",
"value" : {
"US" : {
"type" : "MapVariable",
"name" : "multi_level_map_2_us",
"input" : "threshold",
"defaultValue" : "Unknown",
"value" : {
"Range(0.0,1.0)" : "Low_US",
"Range(1.0,2.0)" : "Medium_US",
"Range(2.0,3.0)" : "High_US"
}
}
}
} ]
}
Deserialization results:
enter image description here
Does anyone know what I am doing wrong and how can I make this recursive deserialization work?

Unable to map json response to Object because of multiple implementations

I have this class structure:
ResponseBody.java:
public class ResponseBody {
private String type;
private A a;
public static class A {
private List<B> b;
}
}
B.java:
public class B {
private String c;
private DynamicJson dynamicJson;
}
DynamicJson.java:
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME,
include = As.PROPERTY, property = "type")
#JsonSubTypes({
#JsonSubTypes.Type(value = Child1.class, name = "child-1"),
#JsonSubTypes.Type(value = Child2.class, name = "child-2"),
#JsonSubTypes.Type(value = Child3.class, name = "child-3")
})
public abstract class DynamicJson {
private String onlyKnownField;
}
Child1.java
#JsonTypeName("child-1")
public class Child1 extends DynamicJson {
// Number of fields and field names here change based on which implementation of Dynamic Json
}
Likewise, Child2 and Child3 classes.
Removed constructors, setters, getters.
I want to cast/deserialize below json to ResponseBody.java class.
{
"type": "child-1",
"a": {
"b": [
{
"c": "guid",
"dynamicJson": {
"onlyKnownField": "guid", // only field that always comes
/*
dynamic number of fields based on "type", say 2 fields, if type is
something else then number of fields here is different
*/
}
}
]
}
}
The field "dynamicJson" can have different number of fields with different names inside it based on "type" value. Which seems to be the problem,
This is the code being used:
ObjectMapper objectMapper = new ObjectMapper();
ResponseBody responseBody = objectMapper.readValue(json.getBody(), ResponseBody.class);
However, above code give this error:
Missing type id when trying to resolve subtype of [simple type, class DynamicJson]
What am I doing wrong here?
Let me know if other info is needed.

Jackson polymorphic deserialization with type property that is nested in one-level higher object

I am stuck deserializing a JSON using Jackson.
JSON objects:
{
"animal": {
"header": {
"id": "1",
"type": "dog"
}
"description": {
"color":"black",
"sound": "bark"
"loyal": true
}
}
{
"animal": {
"header": {
"id": "2",
"type": "cat"
}
"description": {
"color": "white",
"sound": "meow",
"sleepDuration": 14
}
}
{
"plant": {
"header": {
"id": "5",
"type": "rose"
}
"description": {
"color": "red",
"smell": "good"
}
}
Java Classes:
#JsonTypeInfo(
use = JsonTypeInfo.Id.NAME,
include = JsonTypeInfo.As.WRAPPER_OBJECT
)
#JsonSubTypes({
#JsonSubTypes.Type( value = Animal.class, name = "animal" ),
#JsonSubTypes.Type( value = Plant.class, name = "plant")
})
#JsonRootName("species")
public abstract class Species {
public Header header;
public Description description;
//...
}
#JsonRootName("animal")
public class Animal extends Species {
//...
}
#JsonRootName("plant")
#Getter
public class Plant extends Species {
//...
}
#JsonTypeInfo(
// ????????? Not sure if there is an annotation to help with this.
)
#JsonSubTypes({
#JsonSubTypes.Type(name = "DogDescription", value = DogDescription.class),
#JsonSubTypes.Type(name = "RoseDescription", value = RoseDescription.class),
#JsonSubTypes.Type(name = "CatDescription", value = CatDescription.class)})
public abstract class Description {
private String color;
}
#JsonRootName("description")
public class DogDescription {
private Sound sound;
private boolean loyal;
}
#JsonRootName("description")
public class CatDescription {
private Sound sound;
private int sleepDuration;
}
The serialization of animal succeeded. However, I have issue on how to serialize the description using type information in the header.
use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, doesn't work since the type property is not under the Description Object. I have tried also to do a customTypeId resolver as described in this post : Jackson polymorphic deserialization with type property that is nested in object. It didn't work. I think because once the species serialization is performed, Jackson would pass the JSON tree of Description. I couldn't find a way to access the type in the header.
I am wondering if there is a solution to this problem without using a custom serializer.

Unable to process JSON from Jersey via Jackson on Deserialization of polymorphic type

I used the JsonTypeInfo to correctly deserialize the json to appropriate sub-types
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
public abstract class Car {
}
public class Audi extends Car {
// Getters and Setters
}
public class Merc extends Car {
// Getters and Setters
}
For the following structure - Map<String, Car> info
Here is my sample JSON
{
info: {
"xyz": {
type: "Audi"
},
"abc": {
type: "Merc"
}
}
}
The above JSON does not deserialize correctly and get the error 400: Unable to process JSON. What am I missing here ?

Two things, the JSON is incorrect because the properties needs to be between quotes:
{
"info": {
"xyz": {
"type": "Audi"
},
"abc": {
"type": "Merc"
}
}
}
And the second, try to add this annotation to the abstract class:
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
#JsonSubTypes({
#JsonSubTypes.Type(value = Audi.class, name = "Audi"),
#JsonSubTypes.Type(value = Merc.class, name = "Merc")})
abstract class Car {
It basically indicates the subtypes and the names associated.

How to deserialize a json array containing different types of objects

Here is a json snippet which contains an array(icons) which can contain two different types of objects(application and folder)
{
"icons": [
{
"application": {
"displayName": "Facebook",
"bundleId": "com.facebook.com"
}
},
{
"folder": {
"some": "value",
"num": 3
}
}
]
}
How can I create java POJO's modelling this kind of json and then deserialize the same?
I referred to this question. But I can't change the json I'm getting to include a 'type' as advised there and then use inheritance for the POJO's of the two different objects.

No custom deserializers are required. A smart #JsonTypeInfo will do the trick.
See below what the classes and interfaces can be like:
#JsonTypeInfo(use = Id.NAME, include = As.WRAPPER_OBJECT)
#JsonSubTypes({ #Type(value = ApplicationIcon.class, name = "application"),
#Type(value = FolderIcon.class, name = "folder") })
public interface Icon {
}
#JsonRootName("application")
public class ApplicationIcon implements Icon {
public String displayName;
public String bundleId;
// Getters and setters ommited
}
#JsonRootName("folder")
public class FolderIcon implements Icon {
public String some;
public Integer num;
// Getters and setters ommited
}
public class IconWrapper {
private List<Icon> icons;
// Getters and setters ommited
}
To deserialize your JSON, do as following:
String json = "{\"icons\":[{\"application\":{\"displayName\":\"Facebook\",\"bundleId\":\"com.facebook.com\"}},{\"folder\":{\"some\":\"value\",\"num\":3}}]}";
ObjectMapper mapper = new ObjectMapper();
IconWrapper iconWrapper = mapper.readValue(json, IconWrapper.class);