What's the Difference Between `List

Wildcards in Java Generics

Question 1: What is the distinction between List and List?

Answer:

Both List and List are examples of bounded wildcards. An unbounded wildcard is represented as , similar to . This implies that the generic type can be any type without specific constraints.

In contrast, bounded wildcards restrict the type. List is known as an upper-bounded wildcard. It signifies that the generic type must extend T. For instance, List can hold any list that contains subclasses of String (e.g., List or List).

List is known as a lower-bounded wildcard. It specifies that the generic type must be an ancestor of T. For example, List can hold any list that contains superclasses of String (e.g., List