Java 16961 (#13236)

* [JAVA-16961] Moved code for article "Create an Empty Map in Java"

* [JAVA-16961] Alter README.md

* [JAVA-16961] Moved code for article "Sorting a Hashset in Java"

* [JAVA-16961] Added links to README.md files

* [JAVA-16961] Revert link changes

* [JAVA-16961] Replaced junit4 with junit5 annotations

* [JAVA-16961] test build

* [JAVA-16961] Added junit annotations

* [JAVA-16961] Added links

Co-authored-by: panagiotiskakos <panagiotis.kakos@libra-is.com>

core-java-modules/core-java-collections-2/README.md

@@ -13,3 +13,4 @@
 - [Getting the Size of an Iterable in Java](https://www.baeldung.com/java-iterable-size)
 - [Java Null-Safe Streams from Collections](https://www.baeldung.com/java-null-safe-streams-from-collections)
 - [Differences Between Iterator and Iterable and How to Use Them?](https://www.baeldung.com/java-iterator-vs-iterable)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-1) [[next -->]](/core-java-modules/core-java-collections-3)

core-java-modules/core-java-collections-4/README.md

@@ -7,7 +7,6 @@
 - [ArrayList vs. LinkedList vs. HashMap in Java](https://www.baeldung.com/java-arraylist-vs-linkedlist-vs-hashmap)
 - [Java Deque vs. Stack](https://www.baeldung.com/java-deque-vs-stack)
 - [Collection.toArray(new T[0]) or .toArray(new T[size])](https://www.baeldung.com/java-collection-toarray-methods)
-- [Create an Empty Map in Java](https://www.baeldung.com/java-create-empty-map)
 - [Sorting Objects in a List by Date](https://www.baeldung.com/java-sort-list-by-date)
 - [Fixed Size Queue Implementations in Java](https://www.baeldung.com/java-fixed-size-queue)
 - [Difference Between Java Enumeration and Iterator](https://www.baeldung.com/java-enumeration-vs-iterator)
@@ -15,4 +14,4 @@
 - [Guide to Java PriorityQueue](https://www.baeldung.com/java-priorityqueue)
 - [Java Generics PECS – Producer Extends Consumer Super](https://www.baeldung.com/java-generics-pecs)
 - [Reversing a Stack in Java](https://www.baeldung.com/java-reversing-a-stack)
-- [Sorting a HashSet in Java](https://www.baeldung.com/java-sort-hashset)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-3)

core-java-modules/core-java-collections-4/pom.xml

@@ -25,6 +25,12 @@
             <artifactId>commons-lang3</artifactId>
             <version>${commons-lang3.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit-platform.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <properties>

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/collections/comparation/HashMapUnitTest.java

@@ -2,9 +2,7 @@ package com.baeldung.collections.comparation;
 
 import org.junit.jupiter.api.Test;
 
-import java.util.Arrays;
 import java.util.HashMap;
-import java.util.LinkedList;
 import java.util.Map;
 
 import static org.assertj.core.api.Assertions.assertThat;

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/collections/comparation/LinkedListUnitTest.java

@@ -2,10 +2,8 @@ package com.baeldung.collections.comparation;
 
 import org.junit.jupiter.api.Test;
 
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.LinkedList;
-import java.util.List;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/collections/sorting/EmployeeSortingByDateUnitTest.java

@@ -10,7 +10,7 @@ import java.util.Date;
 import java.util.List;
 import org.apache.commons.lang.time.DateUtils;
 import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 public class EmployeeSortingByDateUnitTest {
 

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/collections/sorting/multiple/ComparatorsUnitTest.java

@@ -5,8 +5,9 @@ import java.util.Comparator;
 import java.util.List;
 import java.util.stream.Collectors;
 
-import org.junit.Test;
+
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
 
 public class ComparatorsUnitTest {
     @Test

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/stackreversal/StackReversalUnitTest.java

@@ -1,10 +1,12 @@
 package com.baeldung.stackreversal;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.baeldung.collections.sorting.Employee;
 import com.baeldung.collections.stackreversal.ReverseStackUsingQueue;
 import com.baeldung.collections.stackreversal.ReverseStackUsingRecursion;
-import org.junit.Assert;
+
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import java.util.*;
 import java.util.stream.Collectors;
@@ -15,7 +17,7 @@ public class StackReversalUnitTest {
         ReverseStackUsingQueue reverseStack = new ReverseStackUsingQueue();
         Stack<Integer> originalStack = generateStackFromGivenList(Arrays.stream(new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}).boxed().collect(Collectors.toList()), new Stack<Integer>());
         Stack<Integer> reverseList = generateStackFromGivenList(Arrays.stream(new int[]{10, 9, 8, 7, 6, 5, 4, 3, 2, 1}).boxed().collect(Collectors.toList()), new Stack<Integer>());
-        Assert.assertEquals(reverseStack.reverseIntegerStack(originalStack), reverseList);
+        assertEquals(reverseStack.reverseIntegerStack(originalStack), reverseList);
     }
 
     @Test
@@ -26,7 +28,7 @@ public class StackReversalUnitTest {
         Collections.reverse(listOfWordsReversed);
         Stack<String> originalStack = generateStackFromGivenList(listOfWords, new Stack<String>());
         Stack<String> reversedStack = generateStackFromGivenList(listOfWordsReversed, new Stack<String>());
-        Assert.assertEquals(stackReversal.reverseStringStack(originalStack), reversedStack);
+        assertEquals(stackReversal.reverseStringStack(originalStack), reversedStack);
     }
 
     @Test
@@ -43,7 +45,7 @@ public class StackReversalUnitTest {
         Collections.reverse(employeeReversed);
         Stack<Employee> originalStack = generateStackFromGivenList(employeeList, new Stack<Employee>());
         Stack<Employee> reverseStack = generateStackFromGivenList(employeeReversed, new Stack<Employee>());
-        Assert.assertEquals(stackReversal.reverseEmployeeStack(originalStack), reverseStack);
+        assertEquals(stackReversal.reverseEmployeeStack(originalStack), reverseStack);
     }
 
     @Test
@@ -51,7 +53,7 @@ public class StackReversalUnitTest {
         ReverseStackUsingRecursion reverseStack = new ReverseStackUsingRecursion();
         Stack<Integer> originalStack = generateStackFromGivenList(Arrays.stream(new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}).boxed().collect(Collectors.toList()), new Stack<Integer>());
         Stack<Integer> reversedStack = generateStackFromGivenList(Arrays.stream(new int[]{10, 9, 8, 7, 6, 5, 4, 3, 2, 1}).boxed().collect(Collectors.toList()), new Stack<Integer>());
-        Assert.assertEquals(reverseStack.reverseIntegerStack(originalStack), reversedStack);
+        assertEquals(reverseStack.reverseIntegerStack(originalStack), reversedStack);
     }
 
     private Stack generateStackFromGivenList(List elements, Stack stack){

core-java-modules/core-java-collections-maps/README.md

@@ -12,4 +12,5 @@ This module contains articles about Map data structures in Java.
 - [Immutable Map Implementations in Java](https://www.baeldung.com/java-immutable-maps) 
 - [Guide to Apache Commons MultiValuedMap](https://www.baeldung.com/apache-commons-multi-valued-map)
 - [The Java HashMap Under the Hood](https://www.baeldung.com/java-hashmap-advanced)
+- [Create an Empty Map in Java](https://www.baeldung.com/java-create-empty-map)
 - More articles: [[next -->]](/core-java-modules/core-java-collections-maps-2)

core-java-modules/core-java-collections-maps/pom.xml

@@ -20,6 +20,12 @@
             <artifactId>commons-collections4</artifactId>
             <version>${commons-collections4.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit-platform.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>

core-java-modules/core-java-collections-maps/src/main/java/com/baeldung/map/EmptyMapInitializer.java

@@ -1,7 +1,5 @@
-package com.baeldung.maps.initialize;
+package com.baeldung.map;
 
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Maps;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
@@ -10,6 +8,9 @@ import java.util.NavigableMap;
 import java.util.SortedMap;
 import java.util.TreeMap;
 
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+
 public class EmptyMapInitializer {
 
   public static Map<String, String> articleMap;

core-java-modules/core-java-collections-maps/src/test/java/com/baeldung/map/EmptyMapInitializerUnitTest.java

@@ -1,11 +1,12 @@
-package com.baeldung.maps.initialize;
+package com.baeldung.map;
-
-import java.util.Map;
-import org.junit.Test;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.util.Map;
+
+import org.junit.Test;
+
 public class EmptyMapInitializerUnitTest {
 
   @Test(expected=UnsupportedOperationException.class)

core-java-modules/core-java-collections-set-2/README.md

@@ -2,3 +2,5 @@
 
 - [Using Streams to Collect Into a TreeSet](https://www.baeldung.com/java-stream-collect-into-treeset)
 - [A Guide to LinkedHashSet in Java](https://www.baeldung.com/java-linkedhashset)
+- [Sorting a HashSet in Java](https://www.baeldung.com/java-sort-hashset)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-set)

core-java-modules/core-java-collections-set-2/pom.xml

@@ -15,6 +15,12 @@
     </parent>
 
     <dependencies>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit-platform.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

core-java-modules/core-java-collections-set-2/src/test/java/com/baeldung/hashset/sorting/HashSetUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.collections.sorting;
+package com.baeldung.hashset.sorting;
 
 import static org.assertj.core.api.Assertions.assertThat;