How Do Java Generics Wildcards (Bounded and Unbounded) Enhance Type Flexibility?

Wildcards in Java Generics

Generic wildcards are a powerful feature of Java generics that allow for greater flexibility in type usage. Understanding their behavior is crucial for effectively leveraging them.

Bounded vs. Unbounded Wildcards

An unbounded wildcard is represented as , which essentially signifies . It denotes that the generic type can be any valid Java type.

A bounded wildcard, on the other hand, constrains the generic type by imposing bounds. There are two types of bounded wildcards:

• Upper Bounded Wildcard (): This wildcard specifies that the generic type must be a subtype of T. It allows the list to hold objects of type T or its subclasses.
• Lower Bounded Wildcard (): This wildcard indicates that the generic type must be a supertype of T. It permits the list to contain objects of type T or its ancestor types.

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