Polymorphism without serialized type info (with example) - Jackson JSON User Group

Polymorphism without serialized type info (with example) - Jackson JSON User Group

I am wondering if type info has to be included in the json to deserialize collections when using annotation @JsonDeserialize(contentAs=SomeConcreteClass.class)  .... where the collection would be a Collection<InterfaceClass> and SomeConcreteClass implements InterfaceClass.  Is it because even though I specified the templated class, the type of collection is still unknown (e.g. ArrayList vs HashSet)?  I want the json to be natural and as small a size as possible, and to be able to easily and explicitly annotate what type an object should be deserialized as.  Example classes:

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