<< Chapter < Page Chapter >> Page >
Part of a self-assessment test designed to help you determine how much you know about extending classes, overriding methods, and polymorphic behavior in Java.

Table of contents

Preface

This module is part of a self-assessment test designed to help you determine how much you know about object-orientedprogramming using Java.

The test consists of a series of questions with answers and explanations of the answers.

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.

I recommend that you open another copy of this document in a separate browser window and use the links to under Listings to easily find and view the listings while you are reading about them.

Questions

Question 1 .

What output is produced by the program shown in Listing 1 ?

  • A. Compiler Error
  • B. Runtime Error
  • C. A
  • D. None of the above.
Listing 1 . Listing for Question 1.
public class Ap120{ public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Ap120 class Worker{void doIt(){ Base myVar = new A();myVar.test(); System.out.println("");}//end doIt() }// end class Workerclass Base{ }//end class Baseclass A extends Base{ public void test(){System.out.print("A "); }//end test()}//end class A

Answer and Explanation

Question 2

What output is produced by the program shown in Listing 2 ?

  • A. Compiler Error
  • B. Runtime Error
  • C. A
  • D. None of the above.
Listing 2 . Listing for Question 2.
public class Ap121{ public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Ap121 class Worker{void doIt(){ Base myVar = new A();((A)myVar).test(); System.out.println("");}//end doIt() }// end class Workerclass Base{ }//end class Baseclass A extends Base{ public void test(){System.out.print("A "); }//end test()}//end class A

Answer and Explanation

Question 3

What output is produced by the program shown in Listing 3 ?

  • A. Compiler Error
  • B. Runtime Error
  • C. A
  • D. None of the above.
Listing 3 . Listing for Question 3.
public class Ap122{ public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Ap122 class Worker{void doIt(){ Base myVar = new A();myVar.test(); System.out.println("");}//end doIt() }// end class Workerclass Base{ abstract public void test();}//end class Base class A extends Base{public void test(){ System.out.print("A ");}//end test() }//end class A

Answer and Explanation

Question 4

What output is produced by the program shown in Listing 4 ?

  • A. Compiler Error
  • B. Runtime Error
  • C. A
  • D. None of the above.
Listing 4 . Listing for Question 4.
public class Ap123{ public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Ap123 class Worker{void doIt(){ Base myVar = new A();myVar.test(); System.out.println("");}//end doIt() }// end class Workerabstract class Base{ abstract public void test();}//end class Base class A extends Base{public void test(){ System.out.print("A ");}//end test() }//end class A

Questions & Answers

is economics important in programming world?
Abdul Reply
What is oppunity cost
Kudzanayi Reply
it refers wants that are left unsatisfied in Oder satisfy another more pressing need
Osei
Thank bro
Kudzanayi
is the second altenative to foregone
swedy
How does monopoly and imperfect competion;public goods externalities ass symmetric information, ommon property ressourses; income distribution Merit goods and Macroeconomic growth and stability causes market failure?
Gcina
it is where by a labour moves from one place to another
Amoako Reply
yh
Osei
another
Amoako
yh
Osei
ok
Amoako
what is mobility of labour
George Reply
who best defined economics
paul Reply
what are the importance of economics
Adwoa Reply
answer
Asamoah
trade should be best
Aakash
help to know how our government operates in which system
swedy
1. To solve economic problems. 2. To predict economic event. 3. It also offer intellectual training to students.
samuel
How price elasticity can affect the markets of certain goods
Rhoda Reply
Heyy thanks for the teaching
Easter Reply
what is labour
Arthur Reply
Mental and physical ability of human being is considered as labour.
JEYARAM
and usually provided by human
KEMAWOR
is all human effort both physical and mental abilities to work
Asamoah
why is it that most countries in Africa abuse available resources
Okeoghene Reply
What is economics
Bright Reply
economics is a science which studies human behaviour as a relationship between ends, scarce means which have alternative uses.
prince
Why is scarcity a mind problem in economics
Alima Reply
because of the problem of allocation of resources
Osola
unequalled distribution of resources
Agyen
thanks
Alima
scarcity is a mind problem due to circumstances like when a particular product is demand in a high rate at the market.
Saihou
scarcity defines limited in supply relative to the demand them. so scarcity is a mind problem in economics because wants are unlimited while resources are also limited.
prince
it is a mind problem because it's one of the fundamental issue address by economics human wants are unlimited and resources available are limited this makes the study of economics essential
rashid
its a fundamental issue
zahid
it's not a mind problem, I think it's a economic problem, how to allocate scarce resources to satisfy need and want of society
Samiullah
Identify the different sectors in the economy
Moses Reply
what is economics
Moses
economic is study of human behaviour according to how they satisfie their numerous want
Osola
Economics is a science which studies human behaviour as a relationship between ends and scares resources.
JEYARAM
economic is study of human behaviour according to how they satisfie their numerous want
Amar
what is the law of demand
Adugbire Reply
the lower the price the higher the quantity demanded vice versa is true
Nadhin
yes
vivek
yes ooh
Asamoah
right
samuel
what are relationship between unemployment and economic growth
Weness Reply
no relationship
Awuah
When there is economic growth, there is increased opportunity in employment. When there is no economic growth mean there is recession causing a decline or downsizing in employment opportunities.
Teescou
unemployment or employment determined by the level of economic growth
Osola
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





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