From fe16518c17d7a51abe0940e240d439727b9cde88 Mon Sep 17 00:00:00 2001
From: Sergey Petunin <s.petunin@me.com>
Date: Tue, 16 Aug 2016 13:42:14 +0600
Subject: [PATCH] Added cancellation example for CompletableFuture (#614)

---
 .../CompletableFutureTest.java                | 31 +++++++++++++++----
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/core-java-8/src/test/java/com/baeldung/completablefuture/CompletableFutureTest.java b/core-java-8/src/test/java/com/baeldung/completablefuture/CompletableFutureTest.java
index 806bca5461..e713115cab 100644
--- a/core-java-8/src/test/java/com/baeldung/completablefuture/CompletableFutureTest.java
+++ b/core-java-8/src/test/java/com/baeldung/completablefuture/CompletableFutureTest.java
@@ -1,14 +1,11 @@
 package com.baeldung.completablefuture;
 
-import org.junit.Test;
-
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
+import java.util.concurrent.*;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.junit.Test;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
@@ -46,6 +43,28 @@ public class CompletableFutureTest {
 
     }
 
+
+    public Future<String> calculateAsyncWithCancellation() throws InterruptedException {
+        CompletableFuture<String> completableFuture = new CompletableFuture<>();
+
+        Executors.newCachedThreadPool().submit(() -> {
+            Thread.sleep(500);
+            completableFuture.cancel(false);
+            return null;
+        });
+
+        return completableFuture;
+    }
+
+
+    @Test(expected = CancellationException.class)
+    public void whenCancelingTheFuture_thenThrowsCancellationException() throws ExecutionException, InterruptedException {
+
+        Future<String> future = calculateAsyncWithCancellation();
+        future.get();
+
+    }
+
     @Test
     public void whenCreatingCompletableFutureWithSupplyAsync_thenFutureReturnsValue() throws ExecutionException, InterruptedException {