Jackson Kotlin module library is a pleasure to use. It greatly simplifies gnarly code, specifically one’s involving
TypeReference. 

Consider a sample json which looks like this:

This content can be represented as a “Map<List<String>>” type in Java. 

So now, if I were to use straight Java to convert the string to the appropriate type, the code would look like this:

What exactly is that “TypeReference” doing there… think of it as a way of making the type parameters of the generic type “Map” which are “String” and “List” available at runtime, without that the types are erased at runtime and Java would not know that it has to create a “Map<String, List<String>>”.

Kotlin can hide this detail behind an extension function which if defined from scratch would look like this:

and a code using such an extension function:

See how all the TypeReference related code is well hidden in the extension function. 

This is the kind of capability that is provided by the
Jackson Kotlin Module With the right packages imported a sample code with this module looks like this:

This is just one of the simplifications offered by the use of the module. It also supports features like Kotlin Data classes, Kotlin built-in types like Pair, Triple etc out of the box.

Highly recommended if you are using Jackson with Kotlin.