Can you give examples of reference data types you've encountered?

Reference data types are types that store references to objects in memory, rather than the data itself. Examples of such types in different languages:

• In Java: String, ArrayList, HashMap, user-defined classes (e.g., User, Order)
• In C#: classes (class), interfaces, delegates
• In Python: all objects (lists, dictionaries, strings, classes) are reference types

For example, in Java, a variable of type String contains a reference to a string object in the heap, not the text itself.