Completing and linking tasks asynchronously

Java 8 Concurrency API includes a new synchronization mechanism with the CompletableFuture class. This class implements the Future object and the CompletionStage interface that gives it the following two characteristics:

• As the Future object, a CompletableFuture object will return a result sometime in future
• As the CompletionStage object, you can execute more asynchronous tasks after the completion of one or more CompletableFuture objects

You can work with a CompletableFuture class in different ways:

• You can create a CompletableFuture object explicitly and use it as a synchronization point between tasks. One task will establish the value returned by CompletableFuture, using the complete() method, and the other tasks will wait for this value, using the get() or join() methods.
• You can use a static method of the CompletableFuture class to execute Runnable or Supplier...