How many interfaces can a class implement?

How many interfaces can a class implement?

• A. Exactly one
• B. Several — multiple interface inheritance is allowed
• C. None
• D. Any number of superclasses in addition to interfaces

Answer: (B)

Interfaces define a contract of methods with no implementation, and a class can commit to more than one such contract. A class can implement several interfaces, allowing it to fulfill multiple roles and be used wherever any of those interfaces are required. In practice, there’s no fixed limit on how many interfaces a class can implement, which is why this option—saying you can implement several interfaces—is correct. For example, a class could implement two interfaces to provide different capabilities, while still living in a single class hierarchy. This distinction also contrasts with class inheritance, where many languages restrict a class to one superclass but still allow multiple interfaces to be implemented.

Interfaces define a contract of methods with no implementation, and a class can commit to more than one such contract. A class can implement several interfaces, allowing it to fulfill multiple roles and be used wherever any of those interfaces are required. In practice, there’s no fixed limit on how many interfaces a class can implement, which is why this option—saying you can implement several interfaces—is correct. For example, a class could implement two interfaces to provide different capabilities, while still living in a single class hierarchy. This distinction also contrasts with class inheritance, where many languages restrict a class to one superclass but still allow multiple interfaces to be implemented.