How do I implement variance in Java?

How do I implement variance in Java?

Variance in Java refers to how subtypes relate to super types in generics. You can implement it using wildcards.

What are the differences between covariant and contravariant types?

Covariant types allow you to use a subtype where a supertype is expected, while contravariant types do the opposite.

Can you give me an example of using wildcards in Java?

Sure! You can use <? extends T> for covariance and <? super T> for contravariance in method parameters.

How do I apply this in a real-world scenario?

In a real-world scenario, you might use covariance when dealing with a list of shapes, allowing you to pass a list of specific shapes to a method expecting a list of shapes.