BAEL-3476: Add Java 9 example to Immutable ArrayList in Java (eugenp#…

…8636)

core-java-modules/core-java-9/README.md

@@ -9,6 +9,7 @@ This module contains articles about Java 9 core features
 - [Iterate Through a Range of Dates in Java](https://www.baeldung.com/java-iterate-date-range)
 - [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
 - [Immutable Set in Java](https://www.baeldung.com/java-immutable-set)
+- [Immutable ArrayList in Java](https://www.baeldung.com/java-immutable-list)
 
 Note: also contains part of the code for the article
 [How to Filter a Collection in Java](https://www.baeldung.com/java-collection-filtering).

core-java-modules/core-java-9/pom.xml

@@ -37,6 +37,11 @@
             <version>${junit.platform.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -69,6 +74,7 @@
         <maven.compiler.source>1.9</maven.compiler.source>
         <maven.compiler.target>1.9</maven.compiler.target>
         <guava.version>25.1-jre</guava.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
     </properties>
 
 </project>

core-java-modules/core-java-9/src/test/java/com/baeldung/java9/list/immutable/ImmutableArrayListUnitTest.java

@@ -0,0 +1,48 @@
+package com.baeldung.java9.list.immutable;
+
+import com.google.common.collect.ImmutableList;
+import org.apache.commons.collections4.ListUtils;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class ImmutableArrayListUnitTest {
+
+    @Test(expected = UnsupportedOperationException.class)
+    public final void givenUsingTheJdk_whenUnmodifiableListIsCreated_thenNotModifiable() {
+        final List<String> list = new ArrayList<>(Arrays.asList("one", "two", "three"));
+        final List<String> unmodifiableList = Collections.unmodifiableList(list);
+        unmodifiableList.add("four");
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public final void givenUsingTheJava9_whenUnmodifiableListIsCreated_thenNotModifiable() {
+        final List<String> list = new ArrayList<>(Arrays.asList("one", "two", "three"));
+        final List<String> unmodifiableList = List.of(list.toArray(new String[]{}));
+        unmodifiableList.add("four");
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public final void givenUsingGuava_whenUnmodifiableListIsCreated_thenNotModifiable() {
+        final List<String> list = new ArrayList<>(Arrays.asList("one", "two", "three"));
+        final List<String> unmodifiableList = ImmutableList.copyOf(list);
+        unmodifiableList.add("four");
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public final void givenUsingGuavaBuilder_whenUnmodifiableListIsCreated_thenNoLongerModifiable() {
+        final List<String> list = new ArrayList<>(Arrays.asList("one", "two", "three"));
+        final ImmutableList<String> unmodifiableList = ImmutableList.<String>builder().addAll(list).build();
+        unmodifiableList.add("four");
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public final void givenUsingCommonsCollections_whenUnmodifiableListIsCreated_thenNotModifiable() {
+        final List<String> list = new ArrayList<>(Arrays.asList("one", "two", "three"));
+        final List<String> unmodifiableList = ListUtils.unmodifiableList(list);
+        unmodifiableList.add("four");
+    }
+}

core-java-modules/core-java-collections-array-list/README.md

@@ -3,9 +3,8 @@
 This module contains articles about the Java ArrayList collection
 
 ### Relevant Articles: 
-- [Immutable ArrayList in Java](http://www.baeldung.com/java-immutable-list)
-- [Guide to the Java ArrayList](http://www.baeldung.com/java-arraylist)
-- [Add Multiple Items to an Java ArrayList](http://www.baeldung.com/java-add-items-array-list)
+- [Guide to the Java ArrayList](https://www.baeldung.com/java-arraylist)
+- [Add Multiple Items to an Java ArrayList](https://www.baeldung.com/java-add-items-array-list)
 - [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
 - [Multi Dimensional ArrayList in Java](https://www.baeldung.com/java-multi-dimensional-arraylist)
 - [Removing an Element From an ArrayList](https://www.baeldung.com/java-arraylist-remove-element)

core-java-modules/core-java-collections-array-list/src/test/java/com/baeldung/collections/CoreJavaCollectionsUnitTest.java

@@ -15,42 +15,11 @@ public class CoreJavaCollectionsUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(CoreJavaCollectionsUnitTest.class);
 
-
-    // tests -
-
     @Test
     public final void givenUsingTheJdk_whenArrayListIsSynchronized_thenCorrect() {
-        final List<String> list = new ArrayList<String>(Arrays.asList("one", "two", "three"));
+        final List<String> list = new ArrayList<>(Arrays.asList("one", "two", "three"));
         final List<String> synchronizedList = Collections.synchronizedList(list);
         LOG.debug("Synchronized List is: " + synchronizedList);
     }
 
-    @Test(expected = UnsupportedOperationException.class)
-    public final void givenUsingTheJdk_whenUnmodifiableListIsCreatedFromOriginal_thenNoLongerModifiable() {
-        final List<String> list = new ArrayList<String>(Arrays.asList("one", "two", "three"));
-        final List<String> unmodifiableList = Collections.unmodifiableList(list);
-        unmodifiableList.add("four");
-    }
-
-    @Test(expected = UnsupportedOperationException.class)
-    public final void givenUsingGuava_whenUnmodifiableListIsCreatedFromOriginal_thenNoLongerModifiable() {
-        final List<String> list = new ArrayList<String>(Arrays.asList("one", "two", "three"));
-        final List<String> unmodifiableList = ImmutableList.copyOf(list);
-        unmodifiableList.add("four");
-    }
-
-    @Test(expected = UnsupportedOperationException.class)
-    public final void givenUsingGuavaBuilder_whenUnmodifiableListIsCreatedFromOriginal_thenNoLongerModifiable() {
-        final List<String> list = new ArrayList<String>(Arrays.asList("one", "two", "three"));
-        final ImmutableList<String> unmodifiableList = ImmutableList.<String>builder().addAll(list).build();
-        unmodifiableList.add("four");
-    }
-
-    @Test(expected = UnsupportedOperationException.class)
-    public final void givenUsingCommonsCollections_whenUnmodifiableListIsCreatedFromOriginal_thenNoLongerModifiable() {
-        final List<String> list = new ArrayList<String>(Arrays.asList("one", "two", "three"));
-        final List<String> unmodifiableList = ListUtils.unmodifiableList(list);
-        unmodifiableList.add("four");
-    }
-
 }