### Relevant articles: - [Collect a Java Stream to an Immutable Collection](https://www.baeldung.com/java-stream-immutable-collection) - [Guide to mapMulti in Stream API](https://www.baeldung.com/java-mapmulti) - [Collecting Stream Elements into a List in Java](https://www.baeldung.com/java-stream-to-list-collecting) - [New Features in Java 16](https://www.baeldung.com/java-16-new-features) - [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector) - [Value-Based Classes in Java](https://www.baeldung.com/java-value-based-classes)