Create MethodsToInitializeLinkedList.java (eugenp#17924)

* Create MethodsToInitializeLinkedList.java

* Create LinkedListJUnitTest.java

* Update LinkedListJUnitTest.java

* Update and rename LinkedListJUnitTest.java to LinkedListJUnitTest.java

* Update and rename core-java-modules/core-java-collections-list-2/src/main/java/com/baeldung/java/list/MethodsToInitializeLinkedList.java to core-java-modules/core-java-collections-list-2/src/main/java/com/baeldung/linkedlist/MethodsToInitializeLinkedList.java

core-java-modules/core-java-collections-list-2/src/main/java/com/baeldung/linkedlist/MethodsToInitializeLinkedList.java

@@ -0,0 +1,41 @@
+package com.baeldung.linkedlist;
+
+import java.util.LinkedList;
+import java.util.ArrayList; 
+
+/**
+ *  Demonstrates the different methods to
+ *  initialize a LinkedList.
+ */
+public class MethodsToInitializeLinkedList {
+
+
+    /**
+     * Initialize an Empty List
+     */
+    public void initializeEmptyList() {
+        LinkedList<String> linkedList=new LinkedList<String>();
+
+        linkedList.addFirst("one");
+        linkedList.add("two");
+        linkedList.add("three");
+
+        System.out.println(linkedList);
+    }
+
+    /**
+     * Initialize a List from a Collection
+     */
+    public void initializeListFromCollection() {
+        ArrayList<Integer> arrayList=new ArrayList<Integer>(3);
+
+        arrayList.add(Integer.valueOf(1));
+        arrayList.add(Integer.valueOf(2));
+        arrayList.add(Integer.valueOf(3));
+
+        LinkedList<Integer> linkedList=new LinkedList<Integer>(arrayList);
+
+        System.out.println(linkedList);
+    }
+
+}

core-java-modules/core-java-collections-list-2/src/test/java/com/baeldung/linkedlist/LinkedListJUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.linkedlist;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import java.util.ArrayList; 
+import java.util.LinkedList;
+
+public class LinkedListJUnitTest {
+
+    @Test
+    public void whenInitializingLinkedList_ShouldReturnEmptyList() throws Exception {
+        LinkedList<String> linkedList=new LinkedList<String>();
+
+        Assertions.assertTrue(linkedList.isEmpty());
+    }
+
+    @Test
+    public void whenInitializingListFromCollection_ShouldReturnCollectionsElements() throws Exception {
+        ArrayList<Integer> arrayList=new ArrayList<Integer>(3);
+
+        arrayList.add(Integer.valueOf(1));
+        arrayList.add(Integer.valueOf(2));
+        arrayList.add(Integer.valueOf(3));
+
+        LinkedList<Integer> linkedList=new LinkedList<Integer>(arrayList);
+
+        Object[] linkedListElements = linkedList.toArray();
+        Object[] collectionElements = arrayList.toArray();
+
+        Assertions.assertArrayEquals(linkedListElements,collectionElements);
+    }
+}