Wildcard Type

A ? type argument representing an unknown reference type.

What is Wildcard Type in Java?

Wildcard Type — A ? type argument representing an unknown reference type.

import java.util.List;

class NumberTotal {
    double total(List<? extends Number> values) {
        return values.stream()
                .mapToDouble(Number::doubleValue)
                .sum();
    }
}

Level: Freelancer · More Java terms at this level

Updated