Hello!
I have created a minimal project using the pom and code provided, and I didn't manage to reproduce the error - with only the two elasticsearch dependencies + jackson + the spring bom everything works fine.
SafeResponseConsumer is a class in found in version 8 of the client which extends HttpAsyncResponseConsumer from apache httpcore-nio, I suspect there could be some dependency clashing with other imported libraries (spring security for example) that resolves to the project using a non compatible version of the apache library.
I suggest following the guide provided in the old thread, because the problem seems to be similar.