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The bottom line is that with socket programming, it is easy to write code that will cause a stream of bytes to flow in both directions between a clientand a server. This is no more difficult than causing a stream of bytes to flow in both directions between memory and a file on a disk.

However, getting the bytes to flow is the easy part. Beyond that, you must do all of the programming to implement an application protocol that is understoodby both the client and the server.

URL Programming

URL programming occurs at a higher level than socket programming, and in theory represents a very powerful idea.

In theory, by using the URL class, you can open a connection to a resource on the web, specified by a URL object, and simply call the getContent method on that URL object. The content of the resource will then be magically downloaded and will appear as an object on the clientmachine, even if it requires an application protocol that didn't exist when you wrote the program, and contains content that you didn't understand when youwrote the program.

This description may be a bit of an overstatement, but it is pretty close to the claims being made. This is a powerful idea, which may or may not bear fruitin the future.

If fully implemented by browsers, the idea means that you can place new and unusual material on a web site along with special content handlers and protocolhandlers. Then a cooperating browser will use those special handlers to move that material from the web site to the client and interpret its content once itgets there without a requirement to install software (such as plug-ins) on the client computer on a permanent basis.

Here is what Peter van der Linden has to say about this topic in his excellent book titled Just Java 1.1 and Beyond:

"If a browser doesn't recognize a media type, it should be able to download the code to process it from the same place it got the file. If theyever get this working, it will be ... a good thing."

Is it working, or will they ever get it working? I don't know. If it depends on cooperation among all the major players, including the major browser vendors- probably not. Therefore, I don't plan to spend much time on the topic of protocol and content handlers until I see some evidence that it is working tosuch an extent that it is practically useful.

That is not to say that you couldn't use the capability right now if you were developing an intranet and wanted the clients to have access to new and unusualcontent. It would be necessary for you to provide the appropriate protocol and content handlers, and it would probably be necessary for the clients to run Javaapplications written by you instead of standard browsers to access the data.

Also, the URL class provides an alternative way to connect one computer to another and transfer data on a stream basis, so we will see someexamples of retrieving data from a server by obtaining a URL connection, and then opening and servicing I/O streams between the client and the server. Wewill see some sample programs that make use of this technique, but we will also see that it is somewhat redundant with the socket programming approach.

A local area network

This is part of a sub-collection of modules designed for teaching network programming. Therefore, you may find some of the modules more meaningful if youare able to connect two or more computers in a local area network and run the sample programs across the network.

However, it is possible to simulate a network inside a single computer. If you are unable to create an actual network, you should be able to run all of thesample programs by simulating a network in your single computer.

The operating system

While the capabilities of Java are generally independent of the operating system in use, the manner in which an individual computer must be configured fornetwork operation is generally not independent of the operating system.

In those cases where these modules provide instructions for configuring the computer, those instructions will assume a Windows operating system. If you areusing a different operating system, you will need to translate those instructions into your operating system.

What's Next?

We will learn how to use the Java InetAddress class to find the domain name corresponding to an IP address, and to find the IP addresscorresponding to a domain name in our sample program in the next module.


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java4620: General Information
  • File: Java4620.htm
  • Published: 03/02/14
  • Revised 12/26/14

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 without my prior knowledge.

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


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
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