diff --git a/core-java-modules/core-java-9/README.md b/core-java-modules/core-java-9/README.md
index 2dbf159750..0a9bf76ac4 100644
--- a/core-java-modules/core-java-9/README.md
+++ b/core-java-modules/core-java-9/README.md
@@ -8,5 +8,4 @@ This module contains articles about Java 9 core features
 - [Introduction to Chronicle Queue](https://www.baeldung.com/java-chronicle-queue)
 - [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)
diff --git a/core-java-modules/core-java-collections-set/README.md b/core-java-modules/core-java-collections-set/README.md
index 2b34ef3449..b97cd3216f 100644
--- a/core-java-modules/core-java-collections-set/README.md
+++ b/core-java-modules/core-java-collections-set/README.md
@@ -11,3 +11,4 @@ This module contains articles about the Java Set collection
 - [Guide to EnumSet](https://www.baeldung.com/java-enumset)
 - [Set Operations in Java](https://www.baeldung.com/java-set-operations)
 - [Copying Sets in Java](https://www.baeldung.com/java-copy-sets)
+- [Immutable Set in Java](https://www.baeldung.com/java-immutable-set)
diff --git a/core-java-modules/core-java-9/src/main/java/com/baeldung/java9/set/UnmodifiableSet.java b/core-java-modules/core-java-collections-set/src/main/java/com/baeldung/set/UnmodifiableSet.java
similarity index 97%
rename from core-java-modules/core-java-9/src/main/java/com/baeldung/java9/set/UnmodifiableSet.java
rename to core-java-modules/core-java-collections-set/src/main/java/com/baeldung/set/UnmodifiableSet.java
index 7dbcd2a3a3..2af040b13e 100644
--- a/core-java-modules/core-java-9/src/main/java/com/baeldung/java9/set/UnmodifiableSet.java
+++ b/core-java-modules/core-java-collections-set/src/main/java/com/baeldung/set/UnmodifiableSet.java
@@ -1,4 +1,4 @@
-package com.baeldung.java9.set;
+package com.baeldung.set;
 
 import com.google.common.collect.ImmutableSet;
 
diff --git a/core-java-modules/core-java-9/src/test/java/com/baeldung/java9/SetExamplesUnitTest.java b/core-java-modules/core-java-collections-set/src/test/java/com/baeldung/set/SetExamplesUnitTest.java
similarity index 97%
rename from core-java-modules/core-java-9/src/test/java/com/baeldung/java9/SetExamplesUnitTest.java
rename to core-java-modules/core-java-collections-set/src/test/java/com/baeldung/set/SetExamplesUnitTest.java
index 28e71affcc..d89927dfd6 100644
--- a/core-java-modules/core-java-9/src/test/java/com/baeldung/java9/SetExamplesUnitTest.java
+++ b/core-java-modules/core-java-collections-set/src/test/java/com/baeldung/set/SetExamplesUnitTest.java
@@ -1,9 +1,10 @@
-package com.baeldung.java9;
+package com.baeldung.set;
+
+import org.junit.Test;
 
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
-import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;