## Relevant Articles:
- [Handle Duplicate Keys When Producing Map Using Java Stream](https://www.baeldung.com/java-duplicate-keys-when-producing-map-using-stream)
- [Convert a Stream into a Map or Multimap in Java](https://www.baeldung.com/java-convert-stream-map-multimap)
- [Flatten a Stream of Maps to a Single Map in Java](https://www.baeldung.com/java-flatten-stream-map)