Fixes: #9617 Issue link: https://github.com/spring-projects/spring-integration/issues/9617 The `ListenableFuture` is marked `forRemoval` in Spring Framework. So, fix the code base to use `@SuppressWarnings("removal")`. Also, add a warning into logs that `ListenableFuture` support will be removed in `7.0`. * Fix JavaDocs where `ListenableFuture` is mentioned in favor of `CompletableFuture`