20:38Back adjava300 18-Nov-2022 11-46-...12. Can an object be a subclass of another object?A. Yes as long as single inheritance is followed.B. No inheritance is only between classes.C. Only when one has been defined in terms of the other.D. Yes when one object is used in the constructor of another.13. What is an abstract class?A. An abstract class is one without any child classes.B. An abstract class is any parent class with more than one child class.C.An abstract class is class which cannot be instantiated.D.abstract class is another name for "base class."14. Can an abstract class define both abstract methods and non-abstract methods?A.No it must have all one or the other.B.No it must have all abstract methods.C.Yes but the child classes do not inherit the abstract methods.D.Yes the child classes inherit both.15. Can an abstract method be defined in a non-abstract class?A. No-if a class defines an abstract method the class itself must be abstract.B. No only classes are abstract, not methods.C.Yes-a method can be declared abstract in any parent as long as the child classesalso declare it abstract.Yes there is no restriction on where abstract methods can be defined.D.16. What is polymorphism in Java?A.It is when a single variable is used with several different types of related objects atdifferent places in a program.B. It is when a program uses several different types of objects, each with its ownvariable.C.It is when a single parent class has many child classes.D.It is when a class has several methods with the same name but different parametertypes.17. Given the method declaration below,public void m1 (int num1, int num2) {}which method declaration override method m1 when written in a subclass?A. public void m2 (int numl, int num2) ()B. public void m1 (int num1, double num2) ()C. public string ml (int num1, int num2, int num3) ()D. public int ml (int numl, int num2) ()LTE18. When a class implements an interface, what must it do?A. It must redefine each constant from the interface.B. It must declare and provide a method body for each method in the interface.C. It must declare a variable for each constant in the interface.D. It must include a private method for each method in the interface.19. What is the base class of nearly all Swing classes?a

12. Can an object be a subclass of another object? Inheritance occurs only between the classes and…

12. Can an object be a subclass of another object? A. Yes-as long as single inheritance is followed. B. No inheritance is only between classes. C. Only when one has been defined in terms of the other. D. Yes when one object is used in the constructor of another. 13. What is an abstract class? A. An abstract class is one without any child classes. B. An abstract class is any parent class with more than one child class. C. An abstract class is class which cannot be instantiated. D. abstract class is another name for "base class." 14. Can an abstract class define both abstract methods and non-abstract methods? A. No it must have all one or the other. B. No-it must have all abstract methods. C. Yes but the child classes do not inherit the abstract methods. D. Yes the child classes inherit both.

12. Can an object be a subclass of another object? A. Yes-as long as single inheritance is followed. B. No inheritance is only between classes. C. Only when one has been defined in terms of the other. D. Yes when one object is used in the constructor of another. 13. What is an abstract class? A. An abstract class is one without any child classes. B. An abstract class is any parent class with more than one child class. C. An abstract class is class which cannot be instantiated. D. abstract class is another name for "base class." 14. Can an abstract class define both abstract methods and non-abstract methods? A. No it must have all one or the other. B. No-it must have all abstract methods. C. Yes but the child classes do not inherit the abstract methods. D. Yes the child classes inherit both.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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73. An abstract class is which of the following? a. A class that has direct instances, but whose descendants may have direct instances. b. A class that has no direct instances, but whose descendants may have direct instances. c. A class that has direct instances, but whose descendants may not have direct instances. d. A class that has no direct instances, but whose descendants may not have direct instances
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In order to qualify as a subclass of an abstract class, a class must offer concrete implementations for all of the abstract methods defined in the abstract parent class. Exactly how do you feel about this?
B and C are its subclasses, and A is the parent class. Now, B and C have certain similar features and methods, but B and C implement a number of their methods very differently. Use logic to specify if A is a concrete class, an abstract class, or an interface.
Question 30 Which of the following description is TRUE? Inheritance allows us to define a class based on another class. Child classes receive all the features from the parent class but can NOT have their own additional features. Abstraction means that a method in a parent class can have a number of different implementations in child classes. An interface is a completely abstract class, which contains abstract properties, methods, and variables. The private access modifier makes members accessible only from within the class and hides them from the outside.
Agile methodologies are at their very best with large projects because they are flexible enough to handle whatever needs to be done. O True O False
Class A is the parent class, while classes B and C are the subclasses of A. Both B and C contain several features and techniques that are equivalent to one another; nevertheless, the implementations of some of their methods are quite different between the two. Explain what kind of class A will be using logic, whether it be a concrete class, an abstract class, or an interface.
Weite java code to implement given statements An abstract class must be declared with an abstract keyword.• It can have abstract and non-abstract methods.• It cannot be instantiated.• It can have constructors and static methods also.• It can have final methods which will force the subclass not to change the body of the method.
Class Relationships Exercises 1. In Java, we use inheritance for "is-a" relationships. Containment, on the other hand, indicates that one object has another object. These are "has-a" relationships. For the following relationships, determine if they are a "is-a" or a "has-a" relationship: o bicycle - vehicle o car - engine o pizza - topping o food - pizza o dog - mammal 2. Share with someone else 3 other examples for each of the following relationships: o Inheritance ("is-a" relationship) o Containment ("has-a" relationship) 3. public class PersonInfo { protected String firstName; protected String birthdate; } public class ChildInfo extends PersonInfo { private String schoolName; } public class MotherInfo extends PersonInfo { private String spousename; private ChildInfo children1; private ChildInfo children2; private ChildInfo children3; ... } A. Draw the relationships for the classes above using UML. If a class inherits from another class, draw an open arrow pointing to the base class…
Matched the term or definition with the correct term: Sub Inherits specific members of another class Child 1. Abstraction 2. Base Parent 3. Derived Super 4. Inheritance A class from which another class inherits specific members 5. Interface Object-oriented principle of a class deriving properties from a previously defined class