java8 how to convert Future to CompleteableFuture

Question

I am using jetty websocket api , which returns future for most of its calls.

What is the simple and efficient method for converting Future to CompletableFuture using java8.

I have looked at below links:

1. https://github.com/Spikhalskiy/futurity --> it imports lot of other libraries.

2. Transform Java Future into a CompletableFuture --> acceptable answer uses Future.get() and blocks until completed.