====== Futures ======



Java has 2 main Future implementations:  CompletableFuture and FutureTask.  They both implement the [[https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/concurrent/Future.html|Future]] interface.  Additionally ForkJoinTask implements Future but this is less managable.

===== CompletableFuture =====

CompletableFuture is a full featured Future implementation, capable of chaining and joining.  However, its main weakness is that cancellation doesn't stop the underlying computation, and interruption is not supported.

=== Pain Points ===


  * The exception passed to ''exceptionally()'' and ''handle()'' is not well defined.  It sometimes is a CompletionException.

See Also: [[:futures|Futures]]