<< Chapter < Page Chapter >> Page >
This module contains review questions and answers keyed to the module titled Java3008: Abstract Methods, Abstract Classes, and Overridden Methods.

Revised: Sat Apr 02 20:52:01 CDT 2016

This page is included in the following Books:

Table of contents

Preface

This module contains review questions and answers keyed to the module titled Java3008: Abstract Methods, Abstract Classes, and Overridden Methods .

The questions and the answers are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back again.

Questions

Question 1 .

True or False? The code in Listing 1 produces the output shown in Figure 1 where the two numeric values shown are random but must always match.

Listing 1 . Source code for Java3008r.java.
/*File Java3008r Copyright 2013, R.G.Baldwin Rev 02/12/13*********************************************************/ import java.util.*;abstract class Java3008r{ public static void main(String[]args){ Random generator = new Random(new Date().getTime());int randomNumber = (byte)generator.nextInt(); Java3008r objRef = new Java3008rMyClass(randomNumber);System.out.println(objRef); System.out.println(objRef.getData());System.out.println(randomNumber); }//end main//Declare the signature of an abstract class. public abstract int getData();}//end class Java3008r //======================================================//class Java3008rMyClass extends Java3008r{ private int data;public Java3008rMyClass(int inData){//constructor System.out.println("Java3008r");System.out.println("Dick"); data = inData;}//end constructor public int getData(){//overridden abstract methodreturn data; }//end getData()}//end class Java3008rMyClass

.

Figure 1 . Possible output from the code in Listing 1 .
Java3008r DickBaldwin -80-80

Answer 1

Question 2

True or False? The purpose of an abstract method declaration is to establish the signature of a method that must be overridden in a (non-abstract) subclass of the class in which the abstract method is declared.

Answer 2

Question 3

True or False? When an abstract method is executed, it always exhibits default behavior defined in the class in which it is declared.

Answer 3

Question 4

True or False? An abstract method must be overridden in a subclass in order to be executed.

Answer 4

Question 5

True or False? An abstract method can be overridden once and once only and it must be overridden in the immediate subclass of the class in which it isdeclared.

Answer 5

Question 6

True or False? The existence of an abstract method in a superclass guarantees that objects instantiated from every (non-abstract) subclass of that superclass will have a concrete (executable) version of a method having that same signature.

Answer 6

Question 7

True or False? Any class can be declared abstract. The consequence of declaring a class abstract is that it is not possible to instantiate an objectof the class.

Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
Aislinn Reply
cm
tijani
what is titration
John Reply
what is physics
Siyaka Reply
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Jude Reply
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
David Reply
what is viscosity?
David
what is inorganic
emma Reply
what is chemistry
Youesf Reply
what is inorganic
emma
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
Sahid Reply
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what's motion
Maurice Reply
what are the types of wave
Maurice
answer
Magreth
progressive wave
Magreth
hello friend how are you
Muhammad Reply
fine, how about you?
Mohammed
hi
Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
yasuo Reply
Who can show me the full solution in this problem?
Reofrir Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?

Ask