True or false? An object of a class that implements an interface may be thought of as an object of that interface type.
Answer: True
True or false? If a superclass declares an abstract method, a subclass must implement that method.
True or false? If a superclass declares an abstract method, a subclass must implement that method.
Answer: False
True or false? Invoking a subclass-only method through a subclass variable is not allowed.
True or false? Invoking a subclass-only method through a subclass variable is not allowed.
Answer: False
True or false? All methods in an abstract class must be declared as abstract methods.
True or false? All methods in an abstract class must be declared as abstract methods.
Answer: False
Casting a reference stored in a superclass variable to a subclass type is called __________.
Casting a reference stored in a superclass variable to a subclass type is called __________.
Answer: Downcasting
Methods that are not interface methods and that do not provide implementations must be declared using keyword __________.
Methods that are not interface methods and that do not provide implementations must be declared using keyword __________.
Answer: Abstract
_________ involves using a superclass variable to invoke methods on superclass and subclass objects, enabling you to "program in the general."
_________ involves using a superclass variable to invoke methods on superclass and subclass objects, enabling you to "program in the general."
Answer: Polymorphism
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