1. Comparator example using Lambda and Comparator.comparing corrected.

Author: gschambial

core-java/src/test/java/com/baeldung/comparator/Java8ComparatorUnitTest.java

@@ -17,24 +17,18 @@ public class Java8ComparatorUnitTest {
     @Before
     public void setUp() {
         footballTeam = new ArrayList<Player>();
-        Player player1 = new Player(59, "John", 20);
-        Player player2 = new Player(67, "Roger", 22);
+        Player player1 = new Player(59, "John", 22);
+        Player player2 = new Player(67, "Roger", 20);
         Player player3 = new Player(45, "Steven", 24);
         footballTeam.add(player1);
         footballTeam.add(player2);
         footballTeam.add(player3);
     }
 
     @Test
-    public void whenComparing_UsingJava8_thenSorted() {
+    public void whenComparing_UsingLambda_thenSorted() {
         System.out.println("************** Java 8 Comaparator **************");
-        Comparator<Player> byRanking = new Comparator<Player>() {
-
-            @Override
-            public int compare(Player player1, Player player2) {
-                return player1.getRanking() - player2.getRanking();
-            }
-        };
+        Comparator<Player> byRanking = (Player player1, Player player2) -> player1.getRanking() - player2.getRanking();
 
         System.out.println("Before Sorting : " + footballTeam);
         Collections.sort(footballTeam, byRanking);
@@ -48,8 +42,8 @@ public int compare(Player player1, Player player2) {
     @Test
     public void whenComparing_UsingComparatorComparing_thenSorted() {
         System.out.println("********* Comaparator.comparing method *********");
-        Comparator<Player> byRanking =
-            (Player player1, Player player2)->player1.getRanking()-player2.getRanking();
+        System.out.println("********* byRanking *********");
+        Comparator<Player> byRanking = Comparator.comparing(Player::getRanking);
 
         System.out.println("Before Sorting : " + footballTeam);
         Collections.sort(footballTeam, byRanking);
@@ -58,6 +52,17 @@ public void whenComparing_UsingComparatorComparing_thenSorted() {
             .getName(), "Steven");
         assertEquals(footballTeam.get(2)
             .getRanking(), 67);
+        
+        System.out.println("********* byAge *********");
+        Comparator<Player> byAge = Comparator.comparing(Player::getAge);
+
+        System.out.println("Before Sorting : " + footballTeam);
+        Collections.sort(footballTeam, byAge);
+        System.out.println("After Sorting : " + footballTeam);
+        assertEquals(footballTeam.get(0)
+            .getName(), "Roger");
+        assertEquals(footballTeam.get(2)
+            .getRanking(), 45);
     }
 
 }