Travis no longer supports oraclejdk.

Author: Grundlefleck

.travis.yml

@@ -1,5 +1,5 @@
 language: java
 jdk:
-  - oraclejdk8
+  - openjdk8
 script: "mvn install -DskipTests=true"
 

src/test/java/org/adoptopenjdk/lambda/tutorial/Exercise_5_Test.java

@@ -252,4 +252,8 @@ private Matcher<Song> songBy(String artist) {
         return FeatureMatchers.from(equalTo(artist), "a song by", "artist", Song::getArtist);
     }
 
+    private Matcher<? super List<Song>> containsSongsBy(String... artists) {
+        List<Matcher<? super Song>> songMatchers = Stream.of(artists).map(this::songBy).collect(Collectors.toList());
+        return contains(songMatchers);
+    }
 }