Update README.md

edizor · web-flow · commit 65cc5b6d0504 · 2022-12-22T22:13:12.000+08:00
[skip ci]
diff --git a/core-java-modules/core-java-collections-4/README.md b/core-java-modules/core-java-collections-4/README.md
@@ -15,3 +15,4 @@
 - [Guide to Java PriorityQueue](https://www.baeldung.com/java-priorityqueue)
 - [Java Generics PECS &ndash; Producer Extends Consumer Super](https://www.baeldung.com/java-generics-pecs)
 - [Reversing a Stack in Java](https://www.baeldung.com/java-reversing-a-stack)
+- [Sorting a HashSet in Java](https://www.baeldung.com/java-sort-hashset)
