# Bounded Wildcard

A wildcard restricted to types above or below a stated type in the hierarchy.

## What is **Bounded Wildcard** in Java?

**Bounded Wildcard** — A wildcard restricted to types above or below a stated type in the hierarchy.

```java
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](https://www.ask-codey.com/glossary/subjects/java/freelancer)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/bounded-wildcard