Consuming a json web service and returning that same json

I am writing a Java Web Application using Spring Boot. From my JavaScript code I need to invoke an external web service (not part of my server) however I can't due to CORS security restriction. To circumvent this, I want to create an end point in my own application server that the UI can invoke (without security issue) which will then simply call the external web service and pass back the JSON data as is to the UI.

Request: UI ----> My Server ----> External Web Service Response: UI <--- My Server <---- External Web Service

I want no logic in my server. I just want it to be a dumb passthrough service.

What is the easiest/fasted way to achieve this? Can you please share me a simple code example.