<< Chapter < Page Chapter >> Page >


In this module, I have provided a brief introduction to the use of the Java Collections Framework . The framework is designed to encourage you to reuse rather than to reinvent collections and maps (I will have more to say about maps in a future module).

A collection represents a group of objects, known as its elements.

While some collections allow duplicate elements, others do not. Some collections are ordered and others are not ordered.

The Collections Framework is defined by a set of interfaces and associated contracts. The framework provides concrete implementations of the interfaces (classes) for the most common data structures. In addition, the framework also provides several abstract implementations, which are designed to make iteasier for you to create new and different concrete implementations.

The TreeSet class is a concrete implementation of the SortedSet interface. The SortedSet interface extends Set , which extends Collection . Thus, a TreeSet object is a SortedSet . Also it is a Set , and it is a Collection .

The TreeSet class guarantees that the sorted set will be in ascending element order, and provides guaranteed log(n) time cost for the basic operations( add , remove and contains ).

TreeSet objects can be treated as the generic type Collection . Methods declared in the Collection interface can be called on a Collection object without regard for the actual class from which the object wasinstantiated. (This is polymorphic behavior.)

When such methods are called, the author of the program can have confidence that the behavior of the method will be appropriate for an object of the class from which the object was instantiated. In my opinion, this is thetrue essence of object-oriented behavior.

What's next ?

This is the first module in a miniseries on the Collection Framework . Subsequent modules will teach you how to use the framework for creating andusing various types of collections and maps.

Once you learn how to use the framework, it is unlikely that you will need to reinvent classical data structures, search algorithms, or sorting algorithms,because those capabilities are neatly packaged within the framework.


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java0410: Getting Started with Java Collections
  • File: Java0410.htm
  • Published: 04/18/13

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.

Complete program listing

A complete listing of the program is provided in Listing 6 below.

Listing 6 . Complete program listing.
import java.util.TreeSet; import java.util.Collection;import java.util.Iterator; public class AP400{public static void main( String args[]){ new Worker().doIt();}//end main() }//end class AP400class Worker{ public void doIt(){Collection ref = new TreeSet(); Populator.fillIt(ref);Iterator iter = ref.iterator(); while(iter.hasNext()){System.out.print(iter.next()); }//end while loopSystem.out.println(); }//end doIt()}// end class Worker class Populator{public static void fillIt( Collection ref){ref.add(new Integer(4)); ref.add(new Integer(4));ref.add(new Integer(3)); ref.add(new Integer(2));ref.add(new Integer(1)); }//end fillIt()}//end class populator


Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
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.
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
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
characteristics of micro business
for teaching engĺish at school how nano technology help us
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
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
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.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket 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
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?