From aae74f3b6cce2260442e9c3469f0f22a0f22c319 Mon Sep 17 00:00:00 2001
From: Anshul Bansal <smartdiscover17@gmail.com>
Date: Mon, 8 Apr 2019 11:08:20 +0300
Subject: [PATCH] BAEL-2800_Copying_a_HashMap_in_Java - generic types added

---
 .../baeldung/copyinghashmap/CopyHashMap.java  | 35 ++++++++++---------
 .../copyinghashmap/CopyHashMapUnitTest.java   |  7 ++--
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/core-java-collections-2/src/main/java/com/baeldung/copyinghashmap/CopyHashMap.java b/core-java-collections-2/src/main/java/com/baeldung/copyinghashmap/CopyHashMap.java
index e673335f62..972f48a3bf 100644
--- a/core-java-collections-2/src/main/java/com/baeldung/copyinghashmap/CopyHashMap.java
+++ b/core-java-collections-2/src/main/java/com/baeldung/copyinghashmap/CopyHashMap.java
@@ -2,6 +2,7 @@ package com.baeldung.copyinghashmap;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -9,45 +10,45 @@ import org.apache.commons.lang3.SerializationUtils;
 
 public class CopyHashMap {
     
-    public static HashMap copyUsingConstructor(HashMap originalMap) {
-        return new HashMap(originalMap);
+    public static <K, V> HashMap<K, V> copyUsingConstructor(HashMap<K, V> originalMap) {
+        return new HashMap<K, V>(originalMap);
     }
     
-    public static HashMap copyUsingClone(HashMap originalMap) {
-        return (HashMap) originalMap.clone();
+    public static <K, V> HashMap<K, V> copyUsingClone(HashMap<K, V> originalMap) {
+        return (HashMap<K, V>) originalMap.clone();
     }
 
-    public static HashMap copyUsingPut(HashMap originalMap) {
-        HashMap copyMap = new HashMap();
-        Set<Map.Entry> entries = originalMap.entrySet();
-        for(Map.Entry mapEntry: entries) {
-            copyMap.put(mapEntry.getKey(), mapEntry.getValue());
+    public static <K, V> HashMap<K, V> copyUsingPut(HashMap<K, V> originalMap) {
+        HashMap<K, V> copyMap = new HashMap<K, V>();
+        Set<Entry<K, V>> entries = originalMap.entrySet();
+        for(Map.Entry<K, V> mapEntry: entries) {
+            copyMap.put((K)mapEntry.getKey(), (V)mapEntry.getValue());
         }
         
         return copyMap;
     }
     
-    public static Map copyUsingPutAll(Map originalMap) {
-        HashMap copyMap = new HashMap();
+    public static <K, V> HashMap<K, V> copyUsingPutAll(HashMap<K, V> originalMap) {
+        HashMap<K, V> copyMap = new HashMap<K, V>();
         copyMap.putAll(originalMap);
         
         return copyMap;
     }
     
-    public static HashMap copyUsingJava8Stream(HashMap originalMap) {
-        Set<Map.Entry> entries = originalMap.entrySet();
-        HashMap copyMap = (HashMap) entries
+    public static <K, V> HashMap<K, V> copyUsingJava8Stream(HashMap<K, V> originalMap) {
+        Set<Entry<K, V>> entries = originalMap.entrySet();
+        HashMap<K, V> copyMap = (HashMap<K, V>) entries
             .stream()
             .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
         
         return copyMap;
     }
     
-    public static HashMap shallowCopy(HashMap originalMap) {
-        return (HashMap) originalMap.clone();
+    public static <K, V> HashMap<K, V> shallowCopy(HashMap<K, V> originalMap) {
+        return (HashMap<K, V>) originalMap.clone();
     }
     
-    public static HashMap deepCopy(HashMap originalMap) {
+    public static <K, V> HashMap<K, V> deepCopy(HashMap<K, V> originalMap) {
         return SerializationUtils.clone(originalMap);
     }
     
diff --git a/core-java-collections-2/src/test/java/com/baeldung/copyinghashmap/CopyHashMapUnitTest.java b/core-java-collections-2/src/test/java/com/baeldung/copyinghashmap/CopyHashMapUnitTest.java
index f0434f9bfe..c71e17e94e 100644
--- a/core-java-collections-2/src/test/java/com/baeldung/copyinghashmap/CopyHashMapUnitTest.java
+++ b/core-java-collections-2/src/test/java/com/baeldung/copyinghashmap/CopyHashMapUnitTest.java
@@ -1,6 +1,5 @@
 package com.baeldung.copyinghashmap;
 
-import static org.junit.Assert.assertEquals;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.HashMap;
@@ -21,7 +20,7 @@ public class CopyHashMapUnitTest {
         map.put("emp1",emp1);
         map.put("emp2",emp2);
     
-        HashMap shallowCopy = CopyHashMap.shallowCopy(map);
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
         
         assertThat(shallowCopy).isNotSameAs(map);
         
@@ -36,7 +35,7 @@ public class CopyHashMapUnitTest {
         map.put("emp1",emp1);
         map.put("emp2",emp2);
         
-        HashMap shallowCopy = CopyHashMap.shallowCopy(map);
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
         
         emp1.setName("Johny");
         
@@ -52,7 +51,7 @@ public class CopyHashMapUnitTest {
         Employee emp2 = new Employee("Norman");
         map.put("emp1",emp1);
         map.put("emp2",emp2);
-        HashMap deepCopy = CopyHashMap.deepCopy(map);
+        HashMap<String, Employee> deepCopy = CopyHashMap.deepCopy(map);
         
         emp1.setName("Johny");