![]() An interface can extend another interface,but canot implement anything. Can an interface implement another interface?.Public class AL extends Frame implements WindowListener, ActionListener Yes, a class can implement more than one interface. Can a class implement more than one interface?.Yes, A class that implements an interface can be abstract. Can an abstract class implement an interface?.The method in the class cannot throw an exception unless the Interface itself throws the exception.ĭeclare no checked exceptions on implementation methods other than those declared by the interface method, or subclasses of those declared by the interface method. When a class implements the method of an interface, what must be respected by the method in the class ?.Java runs a compiler check on any class that claims to implement an interface. Upcasting and downcasting in Java Casting : Taking an object of one type and assigning it to reference variable of another type. What does the Java compiler do with any class that claims to implement an interface?.In other words, upcasting allows us to treat a. ![]() How can the following lines of code be rewritten in a more compact manner? Upcasting is converting a derived-class reference or pointer to a base-class.Regardless of whether the superclass declares that it implements the interface, the subclass is not required to re-implement (override) those methods. Learn about Upcasting and Downcasting in Java Full tutorial with concrete examples. non-abstract) method implementations, then, By the way, all Java objects are polymorphic because each object is an Object at least. ![]() Each Cat is an Animal and each Dog is an Animal. ![]() If any superclass in its inheritance tree has already provided concrete (i.e. We add cats and dogs, and they are upcast to Animal type implicitly. You must know what the superclasses of the implementing class have declared.
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