When can you use the instanceof operator?

• A. Only with primitive types
• B. With objects and their types
• C. Only with interface types
• D. Only with Strings

Answer: (B)

The instanceof operator is specifically designed to check whether a given object is an instance of a particular class or implements a specific interface. This means it can be used to determine the type of an object at runtime, making it useful for type checking in polymorphic scenarios.

When you use instanceof, you can compare an object with any class type or interface type in the class hierarchy. For example, if you have an object of a subclass, instanceof will return true if you check it against its parent class or any implemented interfaces. This feature allows for safe downcasting and can prevent runtime exceptions that may occur if an object is of an incompatible type.

The other choices do not accurately reflect the capabilities of the instanceof operator. It is not limited to primitive types, nor is it restricted to interface types or Strings specifically. The operator can be utilized with any object type and their respective class hierarchy.