BAEL-2936

rodrigolgraciano · rodrigolgraciano · commit 3cea8b6df16f · 2019-06-03T23:34:33.000-04:00
diff --git a/java-collections-conversions/src/main/java/com/baeldung/convertToMap/ConvertToMap.java b/java-collections-conversions/src/main/java/com/baeldung/convertToMap/ConvertToMap.java
@@ -15,8 +15,7 @@ public Map<Integer, Book> listToMapWithDupKeyError(List<Book> books) {
     }
 
     public Map<Integer, Book> listToMapWithDupKey(List<Book> books) {
-        return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity(),
-                (o1, o2) -> o1));
+        return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity(), (existing, replacement) -> existing));
     }
 
     public Map<Integer, Book> listToConcurrentMap(List<Book> books) {
diff --git a/java-collections-conversions/src/test/java/com/baeldung/convertToMap/ConvertToMapUnitTest.java b/java-collections-conversions/src/test/java/com/baeldung/convertToMap/ConvertToMapUnitTest.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
 import static org.junit.Assert.*;
@@ -34,8 +35,10 @@ public void whenMapHasDuplicateKey_without_merge_function_then_runtime_exception
     }
 
     @Test
-    public void whenMapHasDuplicateKey_with_merge_function() {
-        assertTrue(convertToMap.listToMapWithDupKey(bookList).size() == 2);
+    public void whenMapHasDuplicateKeyThenMergeFunctionHandlesCollision() {
+        Map<Integer, Book> booksByYear = convertToMap.listToMapWithDupKey(bookList);
+        assertEquals(2, booksByYear.size());
+        assertEquals("0395489318", booksByYear.get(1954).getIsbn());
     }
 
     @Test

Original file line number	Diff line number	Diff line change
`@@ -15,8 +15,7 @@ public Map<Integer, Book> listToMapWithDupKeyError(List<Book> books) {`
`15`	`15`	`}`
`16`	`16`
`17`	`17`	`public Map<Integer, Book> listToMapWithDupKey(List<Book> books) {`
`18`		`- return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity(),`
`19`		`- (o1, o2) -> o1));`
	`18`	`+ return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity(), (existing, replacement) -> existing));`
`20`	`19`	`}`
`21`	`20`
`22`	`21`	`public Map<Integer, Book> listToConcurrentMap(List<Book> books) {`