Which of the following statement(s) is/are True about interfaces? A B с Interfaces are not classes, but like abstract classes; they are a means through which polymorphism can be achieved Interfaces can extend other interfaces Interfaces are abstract classes and are a means through which polymorphism can be achieved

Which of the following statement(s) is/are True about interfaces? A B с Interfaces are not classes, but like abstract classes; they are a means through which polymorphism can be achieved Interfaces can extend other interfaces Interfaces are abstract classes and are a means through which polymorphism can be achieved

EBK JAVA PROGRAMMING

9th Edition

ISBN:9781337671385

Author:FARRELL

Publisher:FARRELL

Chapter11: Advanced Inheritance Concepts

Section: Chapter Questions

Problem 4PE

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Which (if any) of the following conditions are necessary for using polymorphism? Select all correct answers. The classes involved are in the same hierarchy. None of the classes can be abstract. All of the subclasses involved override the same method. The object reference cannot be of an interface type. An object reference of the superclass is used to call any methods. A superclass object is referenced by a subclass reference. Which of the following (if any) are true of abstract methods? Select all correct answers. Abstract methods must have a method body. Abstract methods cannot be declared in a class that isn't abstract itself. Abstract methods cannot be private or static. Abstract methods can only be declared in an interface. Abstract methods cannot be called. Constructor methods can be abstract.
Which (if any) of the following conditions are necessary for using polymorphism? Select all correct answers. The classes involved are in the same hierarchy. None of the classes can be abstract. All of the subclasses involved override the same method. The object reference cannot be of an interface type. An object reference of the superclass is used to call any methods. A superclass object is referenced by a subclass reference. Which of the following (if any) are true of abstract methods? Select all correct answers. Abstract methods must have a method body. Abstract methods cannot be declared in a class that isn't abstract itself. Abstract methods cannot be private or static. Abstract methods can only be declared in an interface. Abstract methods cannot be called.
Which of the following is true about abstract classes? Note that if a class can be sub-classed, this simply means that it can be derived from. Abstract classes can only contain abstract methods. They cannot be sub-classed. Abstract classes cannot be instantiated, but they can be sub-classed. Abstract classes can only contain abstract methods. They can be sub-classed. Abstract classes can be instantiated, but they cannot be sub-classed. Can an interface ever contain method bodies (i.e. content between {})? Unknown Yes No Sometimes
When it is useful to use extension methods? Question 21 options: a) All the answers are correct b) when extending functionalities of an interface type c) When extending functionalities of classes that can't be inherited from (e.g. sealed classes) d) when extending functionalities of a third party library that we don't have access to the source code
Question Kh Write the definition of classes and interfaces in the given diagram using following details: a) Interface shape has a method draw(). b) Override the method draw() in all subclasses. c) Define a non-abstract method fillColor() in Circle class. Full explain this question very fast solution sent me step by step Don't ignore any part all part work u
Create a project Vehicles in bluej. The project has Cars, Buses ,Trucks and Bikesclasses ,all these classes inherit from an interface Vehicle. Pedal_bikesand Motor_bikesare subclasses of abstract class Bikes. A.Show the relationship(class diagrams)between above mentioned classesand interfacesand write the necessary class definitions. B.Interface should have 3 methods: drive(), start() and stop(). C.abstract class Bikesshould have 2abstract methods: speed( ) and getModel( ). D.Which one of the following assignments are legal, why or why not? Justify. Pedal_bikes bik= new Motor_bikes( ); Vehiclev1 = new Buses (); Bikesbi= new Bikes( ) please use BlueJ program.
only in java not in java c++ Create an interface EnhancedShape that extends Shape and also requires a method public double perimeter( ) to be implemented by any class that uses the interface. Create a class file, an interface ehancedshape extends shape, and an interface shape file.
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Abstraction is the basis for good Object-Oriented design that is modular, reusable, and maintainable. Interfaces and Abstract classes are two mechanisms in Java that provide high-level abstractions. An interface or abstract class is something which is not concrete, something which is incomplete. what do you think is meant by “Programming to an interface”? What are some differences between Abstract Classes and Interfaces? Provide a simple example application with an interface definition and a class which implements the interface.
Q2. Write a program (Abstract+Interface) Define a class named Point containing: Two private instance variables x and y of type int. A full parametrized constructor Getters for all instance variables Define an abstract class named Shape containing: An instance variable named s of type Point. A full parametrized constructor A method named getS that returns the value of instance variable An abstract method named Area that has a return type double. Define an interface named Printable containing a method print without parameters and returning void. Define a class named Rectangle which is extended from class Shape, implements the interface printable and containing: Three instance variables named Length, Width of type int and an instance variable named d of type Point. A constructor with two parameters of type Point which initializes all the instance variables. The lengthis the difference in y-coordinates of any top and bottom point. length= Math.abs(s.getY()-d.getY()); The…
Write the definition of classes and interfaces in the given diagram using following details: a) Interface shape has a method draw(). b) Override the method draw() in all subclasses. c) Define a non-abstract method fillColor() in Circle class. (I want the complete solution using the codes in bluej program also diagram) bluej java cood
This is the question - Create an abstract NewspaperSubscription class with fields for the subscriber name, address, and rate. Include get and set methods for the name field and get methods for the address and subscription rate; the setAddress() method is abstract. Create two subclasses named PhysicalNewspaperSubscription and OnlineNewspaperSubscription. The parameter for the setAddress() method of the PhysicalNewspaperSubscription class must contain at least one digit; otherwise, an error message is displayed and the subscription rate is set to 0. If the address is valid, the subscription rate is assigned $15. The parameter for the setAddress() method of the OnlineNewspaperSubscription class must contain an at sign (@) or an error message is displayed. If the address is valid, the subscription rate is assigned $9. Code I was given - public class DemoSubscriptions { public static void main(String args[]) { PhysicalNewspaperSubscription pnsGood = new…