BAEL-5643 : Replace at Specific Index in Java ArrayList (#12539)

core-java-modules/core-java-collections-list-4/src/test/java/com/baeldung/list/replace/ReplaceUsingIndexInArrayListUnitTest.java

@@ -0,0 +1,21 @@
+package com.baeldung.list.replace;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ReplaceUsingIndexInArrayListUnitTest {
+
+    private static final List<Integer> EXPECTED = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5));
+
+    @Test void givenArrayList_updateUsingSet() {
+        List<Integer> aList = new ArrayList<>(Arrays.asList(1, 2, 7, 4, 5));
+        aList.set(2, 3);
+        assertThat(aList).isEqualTo(EXPECTED);
+    }
+}