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This module contains review questions and answers keyed to the module titled Java4090: The Comparator Interface, Part 1.

Revised: Wed Apr 06 23:12:11 CDT 2016

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Table of contents

Preface

This module is one in a collection of modules on Java Collections designed for teaching ITSE2321 - Object-Oriented Programming (Java) at Austin Community College in Austin, TX.

This module contains review questions and answers keyed to the module titled Java4090: The Comparator Interface, Part 1 .

Once you study that module, you should be able to answer the review questions in this module.

The questions and the answers in this module 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 sorting order established by a Comparator must be the same as the natural order.

Answer 1

Question 2

True or False? A Comparator can be used to establish a sorting order for objects that don't have a natural ordering.

Answer 2

Question 3

True or False? The use of a Comparator is an alternative to the implementation of the Comparable interface.

Answer 3

Question 4

True or False? Comparable and Comparator are two different names for the same interface.

Answer 4

Question 5

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

  • Compiler Error
  • Runtime Error
  • 44321
  • 4321
  • 1234
  • 12344

Answer 5

Question 6

True or False? It is possible to instantiate a new TreeSet object using a constructor that receives an incoming reference to a Comparable object, in which case it is not necessary for the objects in the collection to implementthe Comparator interface.

Answer 6

Question 7

True or False? In Listing 1 , the constructor that is called to instantiate a new TreeSet object receives an incoming parameter of type Comparable .

Answer 7

Question 8

True or False? When the fillIt method shown in Listing 1 returns, the collection object referred to by ref will contain references to five objects of type MyClass with those objects encapsulating the values 4, 4, 3, 2, and 1.

Answer 8

Question 9

True or False? When the fillIt method shown in Listing 1 returns, the collection object referred to by ref will contain references to four objects of type MyClass with those objects encapsulating the values 1, 2, 3, and 4 sorted into the order shown.

Answer 9

Question 10

True or False? Given: the Comparator interface declares the two methods listed below:

  • public int compare(Object o1, Object o2)
  • public boolean equals(Object obj)

(Note that the Java documentation would replace the type Object with the generic type T. However, generics are beyond the scope of this course.)

A class that implements the Comparator interface must provide a concrete definition for the compare method but providing a concrete definition for the equals method is optional.

Answer 10

Question 11

True or False? The general behavior of the compare method of a Comparator object compares its two arguments for order and returns a negative integer, zero, or a positiveinteger as the first argument is less than, equal to, or greater than the second.

Questions & Answers

what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
how to synthesize TiO2 nanoparticles by chemical methods
Zubear
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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