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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

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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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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