What differentiates an inner class from a nested class?

• A. Inner classes can be static
• B. Nesting only occurs in public classes
• C. Inner classes are non-static and have access to outer class members
• D. Nesting does not allow access to outer class members

Answer: (C)

Inner classes are defined within the body of an outer class and are inherently non-static. This non-static nature of inner classes allows them to directly access both the instance variables and methods of the outer class, even if they are private. This close linkage between the inner class and its outer class enables a clear and convenient way to leverage the context and state of the outer class without needing external references or methods.

In contrast, a nested class (which may refer to a static nested class) does not have this capability. A static nested class does not have a reference to the instance of the outer class, which means it cannot directly access instance members of the outer class. Hence, the ability of inner classes to access outer class members distinctly characterizes them from nested classes.

The intricacies of inner and nested classes give developers more flexibility in designing their applications, particularly when there is a strong coupling between the inner class's behavior and the outer class's state. This is why the statement regarding inner classes being non-static and having access to the outer class's members is the most accurate depiction of the distinction between the two types of classes.