From 77671ade4b11a5abb8a1651a44a494ce46d351bb Mon Sep 17 00:00:00 2001
From: Harry9656 <singharpal9656@gmail.com>
Date: Tue, 23 Aug 2022 23:22:43 +0200
Subject: [PATCH] JAVA-5683: Difference Between List.of and Arrays.asList
 (#12564)

Co-authored-by: Harpal Singh <harpal.singh@kaleyra.com>
---
 .../core-java-collections-list-4/pom.xml      | 19 ++++++-
 .../list/creation/ArraysAsListUnitTest.java   | 56 +++++++++++++++++++
 .../list/creation/ListOfUnitTest.java         | 51 +++++++++++++++++
 core-java-modules/pom.xml                     |  1 -
 pom.xml                                       |  2 +
 5 files changed, 127 insertions(+), 2 deletions(-)
 create mode 100644 core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ArraysAsListUnitTest.java
 create mode 100644 core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ListOfUnitTest.java

diff --git a/core-java-modules/core-java-collections-list-4/pom.xml b/core-java-modules/core-java-collections-list-4/pom.xml
index ef815b790d..ab4ba37568 100644
--- a/core-java-modules/core-java-collections-list-4/pom.xml
+++ b/core-java-modules/core-java-collections-list-4/pom.xml
@@ -64,6 +64,23 @@
         <colt.version>1.2.0</colt.version>
         <apache-commons.version>3.0</apache-commons.version>
         <assertj.version>3.22.0</assertj.version>
+        <maven.compiler.source.version>17</maven.compiler.source.version>
+        <maven.compiler.target.version>17</maven.compiler.target.version>
+       
     </properties>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source.version}</source>
+                    <target>${maven.compiler.target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
-</project>
\ No newline at end of file
+</project>
diff --git a/core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ArraysAsListUnitTest.java b/core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ArraysAsListUnitTest.java
new file mode 100644
index 0000000000..732dd6a35a
--- /dev/null
+++ b/core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ArraysAsListUnitTest.java
@@ -0,0 +1,56 @@
+package com.baeldung.list.creation;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class ArraysAsListUnitTest {
+
+    @Test
+    void givenAnArrayOfIntegersWhenCreatingAListUsingArraysAsListThenItWillHaveTheSameElementsInTheSameOrder() {
+        Integer[] array = new Integer[]{1, 2, 3, 4};
+        List<Integer> list = Arrays.asList(array);
+        assertThat(list).containsExactly(1, 2, 3, 4);
+    }
+
+    @Test
+    void givenAnListOfIntegersCreatedUsingArraysAsListWhenChangingTheOriginalArrayTheReturnListWillAlsoChange() {
+        Integer[] array = new Integer[]{1, 2, 3};
+        List<Integer> list = Arrays.asList(array);
+        array[0] = 1000;
+        assertThat(list.get(0)).isEqualTo(1000);
+    }
+
+    @Test
+    void givenAnListOfIntegersCreatedUsingArraysAsListWhenChangingTheReturnedListTheOriginalArrayWillAlsoChange() {
+        Integer[] array = new Integer[]{1, 2, 3};
+        List<Integer> list = Arrays.asList(array);
+        list.set(0, 1000);
+        assertThat(array[0]).isEqualTo(1000);
+    }
+
+    @Test
+    void givenAnArrayOfIntegersCreatedUsingArraysAsListWhenModifyingAnExistingElementThenModifyIt() {
+        List<Integer> list = Arrays.asList(1, 2, 3, 4);
+        list.set(1, 1000);
+        assertThat(list.get(1)).isEqualTo(1000);
+    }
+
+    @Test
+    void givenAnArrayCreatedWithArraysAsListWhenAddingANewElementThenUnsupportedOperationExceptionIsThrown() {
+        List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
+        assertThrows(UnsupportedOperationException.class, () -> list.add(6));
+    }
+
+    @Test
+    void givenAnArrayCreatedWithArraysAsListWhenRemovingAnExistingElementThenUnsupportedOperationExceptionIsThrown() {
+        List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
+        assertThrows(UnsupportedOperationException.class, () -> list.remove(1));
+    }
+
+
+}
diff --git a/core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ListOfUnitTest.java b/core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ListOfUnitTest.java
new file mode 100644
index 0000000000..5fe65e965f
--- /dev/null
+++ b/core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/creation/ListOfUnitTest.java
@@ -0,0 +1,51 @@
+package com.baeldung.list.creation;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class ListOfUnitTest {
+
+    @Test
+    void givenAnArrayOfStringWhenCreatingAListUsingItsValuesThenItWillHaveTheSameElementsInTheSameOrder() {
+        String[] array = new String[]{"one", "two", "three"};
+        List<String> list = List.of(array);
+        assertThat(list).containsExactly("one", "two", "three");
+    }
+
+    @Test
+    void givenAnListOfStringCreatedUsingListOfWhenChangingTheOriginalArrayTheReturnListWontChange() {
+        String[] array = new String[]{"one", "two", "three"};
+        List<String> list = List.of(array);
+        array[0] = "thousand";
+        assertThat(list.get(0)).isEqualTo("one");
+    }
+
+    @Test
+    void givenAnArrayCreatedWithListOfWhenAddingANewElementThenUnsupportedOperationExceptionIsThrown() {
+        List<String> list = List.of("one", "two", "three");
+        assertThrows(UnsupportedOperationException.class, () -> list.add("four"));
+    }
+
+    @Test
+    void givenAnArrayCreatedWithListOfWhenRemovingAnExistingElementThenUnsupportedOperationExceptionIsThrown() {
+        List<String> list = List.of("one", "two", "three");
+        assertThrows(UnsupportedOperationException.class, () -> list.remove("two"));
+    }
+
+    @Test
+    void givenAnArrayCreatedWithListOfWhenModifyingAnExistingElementThenUnsupportedOperationExceptionIsThrown() {
+        List<String> list = List.of("one", "two", "three");
+        assertThrows(UnsupportedOperationException.class, () -> list.set(1, "four"));
+    }
+
+    @Test
+    void givenAnArrayContainingNullElementWhenUsingItToCreateListThenNullPointerExceptionIsThrown() {
+        assertThrows(NullPointerException.class, () -> List.of("one", null, "two"));
+    }
+
+
+}
diff --git a/core-java-modules/pom.xml b/core-java-modules/pom.xml
index 981374a4ef..22a7fdec1e 100644
--- a/core-java-modules/pom.xml
+++ b/core-java-modules/pom.xml
@@ -37,7 +37,6 @@
         <module>core-java-collections-list</module>
         <module>core-java-collections-list-2</module>
         <module>core-java-collections-list-3</module>
-        <module>core-java-collections-list-4</module>
         <module>core-java-collections-maps</module>
         <module>core-java-collections-maps-2</module>
         <module>core-java-collections-maps-3</module>
diff --git a/pom.xml b/pom.xml
index 5cf2a2907d..b8a73ad0a0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1161,6 +1161,7 @@
                  <!-- <module>core-java-modules/core-java-16</module> --> <!-- uses preview features, to be decided how to handle -->
                  <!-- <module>core-java-modules/core-java-17</module> --> <!-- uses preview features, to be decided how to handle -->
                  <module>core-java-modules/core-java-collections-set</module>
+                 <module>core-java-modules/core-java-collections-list-4</module>
                  <module>core-java-modules/core-java-collections-maps-4</module>
                  <module>core-java-modules/core-java-date-operations-1</module>
                  <module>core-java-modules/core-java-datetime-conversion</module>
@@ -1234,6 +1235,7 @@
                 <!-- <module>core-java-modules/core-java-16</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-17</module> --> <!-- uses preview features, to be decided how to handle -->
                 <module>core-java-modules/core-java-collections-set</module>
+                <module>core-java-modules/core-java-collections-list-4</module>
                 <module>core-java-modules/core-java-collections-maps-4</module>
                 <module>core-java-modules/core-java-date-operations-1</module>
                 <module>core-java-modules/core-java-datetime-conversion</module>