Java Polymorphic Json Deserialization

Question

I am using jackson as part of serializing and deserializing in my project (Spring Java). In normal scenarios where I have interface(contract) acting as field in POJO, then I use @JsonTypeInfo and @JsonSubTypes to achieve deserialization in polymorphic cases. But, right now, I have scenariio something like this:

public class classA {

    private contractA fieldA;
    
    //constructor and getter-setters.
}

then,

public interface contractA {
}

and finally,

@JsonTypeInfo(
        use = JsonTypeInfo.Id.NAME,
        property = "type")
@JsonSubTypes({
        @JsonSubTypes.Type(/* concrete-class1 as name-value */),
        @JsonSubTypes.Type(/* concrete-class2 as name-value */),
})
public interface contractB extends contractA {
    //contract methods.
}

Now, when classA is passed as controller request body and I pass fieldA as concrete-class1 or concrete-class2 , JsonSubTypes are not being used by jackson to deserialize into one of them. The reason why I did this and had two contracts is due to package dependencies. contractB is in different package as of contractA 's. How can I configure on contractA using jackson that this class has its JsonSubTypeInfo specified in its subclasses.

Or, any other libraries or approaches are also welcomed.

Thank you !

Answer 1

This problem is later on solved by introducing our own custon JsonTypeInfo .

When the application is under deployment, we fetch all subclasses which is present in the JsonTypeInfo annotation (jackson like custom annotaion) and maintain a data-structure, that will be used while serializing and deserializing . This process is somewhat similar to the Jackson one (in addition to lookup for nested hierarches as well).