<< Chapter < Page Chapter >> Page >

The Collections Framework is defined by a set of interfaces and associated contracts, and provides concrete implementations of the interfaces for the mostcommon data structures. In addition, the framework also provides several abstract implementations, which are designed to make it easier for you to createnew and different implementations while still maintaining the structural polymorphic integrity of the framework.

Generics

The code in this series of modules is written with no thought given to Generics . As a result, if you copy and compile the code, you will probably get warnings about unchecked or unsafe operations .

While you will ultimately need to understand how to use Generics, that is a very complex topic. An understanding of Generics is beyond the scope of thiscourse. Therefore, for purposes of this course, you can simply ignore those warnings.

Introduction

A quiz

Let's begin with a little quiz to establish your baseline knowledge of the Collections Framework. Take a look at the program in Listing 6 near the end of this module. Which of the following is the output produced by that program?

  • A. Compiler Error
  • B. Runtime Error
  • C. 44321
  • D. 12344
  • E. 1234
  • F. None of the above.

If your answer was 1234 (and it wasn't a guess) then you may already know quite a lot about the use of the Collections Framework. If not, keep reading to begin learning aboutthe framework.

Elements of the Framework are easy to use

This simple introductory program is not intended to do anything useful. Instead, it was designed to illustrate several important features of theframework, including the ease with which elements of the framework can be reused in your programs.

Don't reinvent the wheel

As many of you already know, I am a college professor. I specialize in teaching OOP using Java. In the past, many college courses in Data Structures (often referred to as CS2 courses) have emphasized the concept of reinventing the wheel . Students were required to learn how to reinvent a variety of complex data structures in order to successfully complete the course.

Hopefully, with the conversion of these CS2 courses to Java OOP, the emphasis will change to reuse instead of reinvent .

Collections Framework encourages reuse

The Java Collections Framework is designed to encourage programmers to reuse existing interfaces and classes instead of inventing new ones. In the event thatit is necessary to invent a new class or interface, the programmer is encouraged to integrate it into the framework in a polymorphic manner.

Sample program

I am going to provide a brief discussion of the sample program (shown in Listing 6 ) in this module. Later, I will provide more detailed discussions of many of the features used in that program.

Interesting code fragments

I will break this program down and discuss it in fragments.

An object of the TreeSet class

The code fragment in Listing 1 instantiates an object of the TreeSet class and stores the object's reference in a reference variable of type Collection named ref .

Listing 1 . A new object of the TreeSet class.
class Worker{ public void doIt(){Collection ref = new TreeSet();

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
Introduction about quantum dots in nanotechnology
Praveena Reply
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
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
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
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Mueller Reply
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