abstract class Worker<T>

class WhatAmI : Worker<String>() {
  val type = (this::class.java.genericSuperclass as ParameterizedType).actualTypeArguments[0]
}

fun main() {
 println(WhatAmI().type)
}

abstract class MyWorker<T : Any> {
        private lateinit var objectMapper: ObjectMapper

        abstract fun handleMessage(message: String)

        inline fun <reified V : T> doWorkWithMessage(message: String) {
            doWorkWithMessage(message, V::class.java)
        }

        fun <V : T> doWorkWithMessage(message: String, clazz: Class<V>) {
            val payload = objectMapper.readValue(message, clazz)
            work(payload)
        }

        protected abstract fun work(payload: T)
    }

    // Here I need to specify ExamplePayload twice:
    class MyExampleWorker : MyWorker<ExamplePayload>() {
        override fun handleMessage(message: String): Unit = doWorkWithMessage<ExamplePayload>(message)

        override fun work(payload: ExamplePayload) {
            TODO("not implemented")
        }
    }