Why Data stax enterprise java driver Async methods returns Guava's ListenableFutures instead of Java's CompletableFutures?

Question

All the Async methods of DataStax Enterprise Driver uses Guava library to return features, Which are call back based, Why the APIs are not exposed to return Java's CompletableFutures

Answer 1

Because the current version of driver (3.x) is aiming the users of the Java 6 & 7, and CompletableFuture is available in the Java 8. The new version of driver (4.x, currently in alpha stage) will drop support for Java 6 & 7, and will switch from Guava's futures.

See DataStax JIRA for discussion of related stuff. And this question in new driver's FAQ.