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Answer and Explanation

Question 10

What output is produced by the program shown in Listing 10 ?

  • A. Compiler Error
  • B. Runtime Error
  • C. Base
  • D. A B
  • E. None of the above.
Listing 10 . Listing for Question 10.
public class Ap129{ public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Ap129 class Worker{void doIt(){ Base myVar = new A();myVar.test(); myVar = new B();myVar.test(); System.out.println("");}//end doIt() }// end class Workerclass Base{ public void test(){System.out.print("Base ");}; }//end class Baseclass A extends Base{ public void test(){System.out.print("A "); }//end test()}//end class A class B extends Base{public void test(){ System.out.print("B ");}//end test() }//end class B

Answer and Explanation

Listings

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Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Ap0110: Self-assessment, Extending classes, overriding methods, and polymorphic behavior
  • File: Ap0110.htm
  • Originally published: 2002
  • Published at cnx.org: 12/08/12
  • Revised: 12/03/14
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Answers

Answer 10

D. A B

Explanation 10

Another illustration of simple polymorphic behavior

In this program, two classes named A and B extend the class named Base , each overriding the method named test to produce different behavior. (Typically, overridden methods in different classes will produce different behavior, even though they have the same names.)

Behavior appropriate for object on which method is called

Questions & Answers

calculate molarity of NaOH solution when 25.0ml of NaOH titrated with 27.2ml of 0.2m H2SO4
Gasin Reply
what's Thermochemistry
rhoda Reply
the study of the heat energy which is associated with chemical reactions
Kaddija
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Edafe Reply
explain please
Victory
First twenty elements with their valences
Martine Reply
what is chemistry
asue Reply
what is atom
asue
what is the best way to define periodic table for jamb
Damilola Reply
what is the change of matter from one state to another
Elijah Reply
what is isolation of organic compounds
IKyernum Reply
what is atomic radius
ThankGod Reply
Read Chapter 6, section 5
Dr
Read Chapter 6, section 5
Kareem
Atomic radius is the radius of the atom and is also called the orbital radius
Kareem
atomic radius is the distance between the nucleus of an atom and its valence shell
Amos
Read Chapter 6, section 5
paulino
Bohr's model of the theory atom
Ayom Reply
is there a question?
Dr
when a gas is compressed why it becomes hot?
ATOMIC
It has no oxygen then
Goldyei
read the chapter on thermochemistry...the sections on "PV" work and the First Law of Thermodynamics should help..
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Which element react with water
Mukthar Reply
Mgo
Ibeh
an increase in the pressure of a gas results in the decrease of its
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definition of the periodic table
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what were atoms composed of?
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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
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