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If a class has a field of the same name as any field visible to it on any of its
superclasses or superinterfaces, the subclass' field is said to
"[hide](https://docs.oracle.com/javase/tutorial/java/IandI/hidevariables.html)"
the superclass' field.
When this circumstance occurs, users of the class declaring the hiding field
can't interact with the fields from the superclass.
Let's take a look at how field hiding might cause problems:
```java
class Super {
public String foo = "bar";
}
class Sub extends Super {
private int foo = 0; // the same name, so this hides `Super`'s `foo`
}
class Main {
void stringFn(String s) { /*...*/ }
public static void main(String... args) {
// Looking at the API of `Super`, I should be able to access a string `foo`
// on any object of type `Super` or its subclasses, right?
stringFn(new Sub().foo); // Oops! `foo` is not visible, and the wrong type!
}
}
```
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