Differences between CompletableFuture and Future in Java 9?

CompletableFuture<T> class implements Future<T> interface in Java. CompletableFuture can be used as a Future that has explicitly completed. The Future interface doesn’t provide a lot of features, we need to get the result of asynchronous computation using the get() method, which is blocked, so there is no scope to run multiple dependent tasks in a non-blocking fashion whereas CompleteFuture class can provide the functionality to chain multiple dependent tasks that run asynchronously, so we can create a chain of tasks where the next task is triggered when the result of the current task is available.

Syntax

public class CompletableFuture<T> extends Object implements Future<T>, CompletionStage<T>

Example

import java.util.function.Supplier; import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutionException; public class CompletableFutureTest {    public static void main(String args[]) throws ExecutionException, InterruptedException {       Calculator calc = new Calculator(4, 7);       CompletableFuture<Integer> future = CompletableFuture.supplyAsync(calc);       future.thenAccept(result -> {          System.out.println(result);       });       System.out.println("CompletableFutureTest End.... ");       Thread.sleep(10000);    } } // Calculator class class Calculator implements Supplier<Integer> {    private int x, y;    public Calculator(int x, int y) {       this.x = x;       this.y = y;    }    @Override    public Integer get() {       try {          Thread.sleep(3000);       } catch(InterruptedException e) {          e.printStackTrace();       }       return x + y;    } }

Output

CompletableFutureTest End.... 11