Java Concurrency Wrap Elasticsearch Response Into CompletableFuture Why Do We Need Completable Future? Write An Actor In Akka 3 Ways to Handle Exception In Completable Future How CompletableFuture is tested in OpenJDK? Asynchronous Processing in JAX-RS 2.x Akka: Testing Actor with TestActorRef ExecutorService.invokeAll() Method Execution In Multithreading Introduction to Threads