Spring The existence of org.springframework.util.concurrent.ListenableFuture is confusing.

ListenableFuture has been created since Spring 4.0. Although Spring 4.0 supported Java 8, the minimum requirement was Java 6, so the existence of ListenableFuture is understandable. However, since 5.0, Spring requires Java 8 as a minimum. Java 8 includes CompletableFuture which can replace ListenableFuture.

Without knowing this history, it can be confusing why ListenableFuture exists. What do you think about removing ListenableFuture?

Comment From: poutsma

If we change all methods that use ListenableFuture to CompletableFuture, we would force all consumers of these methods to change their code as well. We try not to break backwards compatibility without a very good reason.