## Java Collections Cookbooks and Examples This module contains articles about Map data structures in Java. ### Relevant Articles: - [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)