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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

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
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.
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
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
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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