What are wildcards in Java generics?

What are wildcards in Java generics?

Wildcards in Java generics are special symbols that allow you to specify a range of types. They are represented by the '?' character.

Can you explain the different types of wildcards?

Sure! There are three types of wildcards: unbounded wildcards (?), upper bounded wildcards (? extends T), and lower bounded wildcards (? super T).

When should I use each type of wildcard?

Use unbounded wildcards when you don't care about the type, upper bounded wildcards when you want to restrict to a specific type or its subclasses, and lower bounded wildcards when you want to restrict to a specific type or its superclasses.

Can you give an example of using wildcards in a method?

Certainly! Here's an example: public static <T> void printList(List<? extends T> list) { for (T item : list) { System.out.println(item); } } This method can accept a list of any type that extends T.