Hands-On Reactive Programming in Spring 5

JDK 9

Likewise, the value of specification was seen by the JDK implementing team too. Not long after the first release of the specification, Doug Lee created a proposal to add the aforementioned interface in JDK 9. The proposal was supported by the fact that the current Stream API offers just a pull model, and a push model was a missing point here:

"…there is no single best fluent async/parallel API. CompletableFuture/CompletionStage best supports continuation style programming on futures, and java.util.Stream best supports (multi-stage, possibly-parallel) “pull” style operations on the elements of collections. Until now, one missing category was “push” style operations on items as they become available from an active source."

- Doug Lee,  ...