CompletableFuture is used for asynchronous programming in Java. Asynchronous programming is a means of writing non-blocking code by running a task on a separate thread than the main application thread and notifying the main thread about its progress, completion or failure.

What does CompletableFuture get do?

Instead of catching an exception in a syntactic block, the CompletableFuture class allows us to handle it in a special handle method. This method receives two parameters: a result of a computation (if it finished successfully), and the exception thrown (if some computation step did not complete normally).

What is the difference between Future and CompletableFuture?

While using Future, we do not get notified when it is complete neither does it provides us a callable method which will automatically be called when the result is available but CompletableFuture provides us with a lot of callable methods which can be used as per our use case.