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  • Collection
    • Set
      • SortedSet
    • List
    • Queue
    • Deque
  • Map
    • SortedMap

As you can see, as mentioned earlier, Collection and Map are the two top-level interfaces.

You should probably commit the above list of interfaces and their relationships to memory. You might find that helpful when navigating the Oracledocumentation.

Concrete implementations

In addition to interfaces, the framework provides several concrete implementations of the interfaces defined in the framework. (A concrete implementation is a class that implements one or more of the interfaces.)

Are you still awake? If so, see if you can answer the following question.

True or False? Each of the following classes provides an implementation of one of the interfaces that make up the Java Collections Framework. If False,which items don't belong in the list.

  • AbstractSet
  • AbstractList
  • AbstractMap
  • HashSet
  • TreeSet
  • LinkedList
  • Vector
  • ArrayList
  • HashMap
  • Hashtable
  • WeakHashMap
  • TreeMap
  • Iterator
  • Attributes
  • RenderingHints

Hopefully your answer was False, but even so, that isn't the complete answer.

Iterator is not a class

To begin with, Iterator is not a class. I told you that a couple of paragraphs back. It is an interface. Therefore, it has no place in theabove list of classes.

What about Attributes and RenderingHints?

You may also have wondered if the classes named Attributes and RenderingHints belong on the list. Note that I didn't restrict the above list to only those classes that might be considered part of the framework, sothis was sort of a trick question. (Of course you could have looked them up in the Oracle documentation just like I did.)

While these two classes are not really a part of the core Java Collections Framework, they do implement interfaces that are part of the framework.

The RenderingHints class implements the Map interface, and is used in conjunction with the Graphics2D class. The Attributes class also implements the Map interface,

What is a Collections Framework?

According to The Java Tutorial from Oracle, "A collections framework is a unified architecture for representing and manipulating collections. Allcollections frameworks contain three things."

Those three things are:

  • Interfaces
  • Implementations
  • Algorithms

This is probably a good place to close off the discussion for this module. The next module will pick up at this point and provide a more in-depth discussion ofthe interfaces, implementations, and algorithms that make up the framework.

Summary

I started out by telling you that a collection is not only the name of a Java interface (Collection) but is also an object that groups multiple elements into a single unit.

Java Collection objects don't store objects or primitive values directly. Rather, they store references to objects. Further, all such referencesare stored as the type Object . However, the use of the Generics syntax can eliminate the need todowncast the reference in order to gain access to the members of the object to which it refers. (Generics also provide other useful properties as well.)

If you need to store primitive values in a collection, you will first need to wrap those values in appropriate objects. Standard wrapper classes are providedfor all the primitive types.

Collections are not only useful for storing and retrieving data, they are also useful for moving data among methods.

Because a collection can be passed to a method as type Collection , all of the methods declared in the Collection interface can be called on the incoming reference in a polymorphic manner.

In addition to the interfaces defined in the Collections Framework, the framework also provides various concrete implementations of the interfaces formany of the commonly-used data structures. This makes it possible for you to conveniently use the framework without the requirement to define new Collection classes.

There are eight core interfaces in the Collections Framework. Although the Iterator interface is often used with collections, it is not one of the core interfaces.

I ended the module by telling you that there are basically three things in a collections framework: interfaces , implementations , and algorithms . I will have more to say about this in a future module.

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java4020: What is a Collection
  • File: Java4020.htm
  • Published: 04/18/13
Disclaimers:

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.

-end-

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris 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
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
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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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