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SCJA-drills-chap08
Question | Answer |
---|---|
What does polymorphism stimulate? | Polymorphism stimulates code reuse. |
What does polymorphism allow? | Polymorphism allows one object to act as either one of its superclasses, or as an interface that it implements. |
Define the relation between subclass and class. | A subclass (more specific) “is-a” superclass (more general) object. |
Explain the meaning of "Polymorphism is unidirectional". | More specific objects can only polymorphically act as more general objects. |
Explain how interfaces are used in relation with polymorphism. | By implementing an interface, an object is declaring it has the functionality defined in the interface. This allows that object to polymorphically act as the interface. |
What is programming to an interface? | Programming to an interface is the concept where the developer defines the required functionality instead of defining strict object data types. |
What does programming to an interface allow? | Programming to an interface allows other developers to interact with the code using any object they choose as long as it implements the required interfaces. |
What is an object interchangeable with, and what characteristic related to casting does this have? | An object can be used interchangeably with any of its superclasses and with any interface it implements, without the need to be cast. |
What is the consequence of using a more specific object polymorphically as a general one? | When a more specific object is polymorphically used as a general object, the more specific functionality is not available. |
In with context is, as an example, polymorphism commonly used? | Polymorphism is commonly used for method arguments. |