diff --git a/core-java-modules/core-java-collections-maps-4/README.md b/core-java-modules/core-java-collections-maps-4/README.md
index 795f0df702..a3f40d5ab7 100644
--- a/core-java-modules/core-java-collections-maps-4/README.md
+++ b/core-java-modules/core-java-collections-maps-4/README.md
@@ -6,3 +6,4 @@ This module contains articles about Map data structures in Java.
 - [Using a Custom Class as a Key in a Java HashMap](https://www.baeldung.com/java-custom-class-map-key)
 - [Nested HashMaps Examples in Java](https://www.baeldung.com/java-nested-hashmaps)
 - [Java HashMap With Different Value Types](https://www.baeldung.com/java-hashmap-different-value-types)
+- [Difference Between Map and HashMap in Java](https://www.baeldung.com/java-map-vs-hashmap)