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This weeks Giveaway

Carl Trusiak
Sheriff

Joined: Jun 13, 2000
Posts: 3340
This week we are giving away 4 copies of the book Early Adopter JXTA.
The best part, the Author Sing Li is on-line to answer your questions.
Thanks to the good folks at Wrox for the books
Doug Wang
Ranch Hand

Joined: Oct 05, 2001
Posts: 445
Hello Sing Li,
Welcome to this ranch! And May you a happy Spring Festival!


Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep
Doug Wang
Ranch Hand

Joined: Oct 05, 2001
Posts: 445
Sing Li,
You are also the author of another distributed java book _Professional Jini_. Could you give us a concise explanation on the difference b/w these two technologies? How do these two fit for Web Services?
Thanx.
[ February 12, 2002: Message edited by: Doug Wang ]
Michael Ernest
High Plains Drifter
Sheriff

Joined: Oct 25, 2000
Posts: 7292

For those of you interested in Jini, Sing Li's book Professional Jini is an outstanding resource for programmers wanting to learn the power of RMI and Jini takes advantage of it.
JXTA leverages the power of network communication in a manner similar to Jini, although the construction of the programming tools seems quite different. In a Jini environment, it's plausible to have services that also behave as clients, but you have to think through it to make it work (not to mention finding a good reason for doing it ).
JXTA is more than just a way to program file sharing, although Napster and other music-sharing services have done a lot to popularize the age-old concept of P2P. By extending the concept of network communities so all participants inherently send and receive data/code, you can express some very powerful computing ideas.
Let's take an example: 50 of us have a machine, and we're all over the place. We work in staggered shifts, and while our systems are idle we're decoding a genome together. My system goes out at some point and asks the other 49, "who has the genome data?" System 25 replies, "I do." My system says, "when you are done with it, I have a 10-hour window here of uninterrupted process time." System 25 says, "Cool, you want this whole job (and the responsibility for passing it forward in whatever state), or just a piece that will fit that resource window?"
You can imagine the rest from there. There's no central computational resource, just networking services that register and deregister clients in the community, such that the network picture of what's going on is described, but not mastered by any one machine.


Make visible what, without you, might perhaps never have been seen.
- Robert Bresson
Latha Kalaga
Ranch Hand

Joined: Nov 13, 2000
Posts: 96
Hi Michael,
Jini and Jxta seem to have been developed to tackle the similar problem (peer-to-peer computing). Can you please be more specific on how Jxta can be applied to a specific problem while Jini comes up short?
Thanks,
Latha
Simon Xu
Ranch Hand

Joined: Aug 16, 2000
Posts: 235
Welcome, Li Sing,
Can you outline the contents of your book? Thanks
Michael Ernest
High Plains Drifter
Sheriff

Joined: Oct 25, 2000
Posts: 7292

Latha - Jini is not intended as a P2P model, plain and simple. That's all I'll say; I don't want to steal Sing's thunder.
Simon - can you perhaps develop a more interesting question for Sing than asking him to recite the table of contents? You can get that information from Fatbrain or Amazon. Let's use Sing's time wisely; what do you want to know about JXTA?
[ February 12, 2002: Message edited by: Michael Ernest ]
Anonymous
Ranch Hand

Joined: Nov 22, 2008
Posts: 18944
Hi Sing Li,
All I could say is Welcome and thank you.
Yoel Stern
Fei Ng
Ranch Hand

Joined: Aug 26, 2000
Posts: 1242
Sing Li,
Welcome to javaranch. Hope you have a nice stay!
and congratulations on 5 starts rating at amazon.

john
[ February 12, 2002: Message edited by: FEI NG ]
Sing Li
Author
Greenhorn

Joined: Feb 12, 2002
Posts: 17
Doug,
Thank you for the greeting.
Regarding your question:
Jini is Java centric distributed computing fabric and leverages Java�s code mobility to its advantage. JXTA is an interoperable, protocol based, P2P networking fabric that has no dependency whatsoever on Java � in fact, implementations of JXTA in C, Perl, and Python are being created as we speak. In addition, JXTA is an open source project, but commercial use of Jini is subjected to licensing fees from SUN.
Michael,
Thank you very much for your kind words, and the great explanation!
Simon,
Thanks for the welcome, and please see this page for the summary of the book:
http://www.wrox.com/ACON11.asp?WROXEMPTOKEN=15162ZVMYdqNUmNFtWda5QPsdL&ISBN=1861006357

Latha,
Michael is right on the money. Jini is for distributed computing while JXTA is for P2P. While one can possibly configure one to do the job of the other � in typical applications, they are quite different.
Yoel and John,
Thank you for the welcome!
Best Regards,
Sing Li
Doug Wang
Ranch Hand

Joined: Oct 05, 2001
Posts: 445
Sing Li,
Thanks for your explanation.
Here is Li Gong, Jxta architect's talk at JavaOne conference supports your views [on Jini and Jxta]:
"Jini and Jxta started from different premises. Jini started with the premise that both ends have JVMs (1.3 and upward). So if you depend on both ends having JVMs, there are lots of things you could do. On the other hand, you are also constrained. Of course the surrogate architecture will help Jini to interface with devices that are not fully Jini-compliant. Jxta started with a much lower premise. The only assumption [Jxta makes is that] there's something that implements the protocol. This gives a wider field to play in... [Jini and Jxta] are different but complementary in the sense that it's very easy to imagine Jini being used to provide directories for Jxta networks. People who have Jini and have Java can do more ... you get a maximum return if Java is on both ends; there's no doubt about it."

[ February 14, 2002: Message edited by: Doug Wang ]
Fei Ng
Ranch Hand

Joined: Aug 26, 2000
Posts: 1242
Hi,
Been reading this thread and Jxta is very interesting. Is there a live sample or code that we can take a look?
Any company that use Jxta implement right now?
thanks.
ps: great exmaple Michael !
[ February 14, 2002: Message edited by: FEI NG ]
Doug Wang
Ranch Hand

Joined: Oct 05, 2001
Posts: 445
Hi John,
Here are two articles by Sing Li give you examples of JXTA:
Making P2P interoperable: The Jxta command shell
and
Rock 'em, sock 'em Robocode! (a Jxta-like app)
Also browse Project JXTA, you'll find many projects of Jxta apps, demos and tutorials.
[ February 14, 2002: Message edited by: Doug Wang ]
Fei Ng
Ranch Hand

Joined: Aug 26, 2000
Posts: 1242
thanks Doug,
Very helpfull INFO! JXTA is really interesting..
How do you see it Doug?
Sing Li
Author
Greenhorn

Joined: Feb 12, 2002
Posts: 17
Thank you, everyone, for a fascinating discussion this week and posting excellent questions. Congrats to the lucky winners.
Anybody who is interested in JXTA should definitely check out the open source site where everything is happening. http://www.jxta.org/ It is where I hang out. There are many commercial companies that are profiled there, complete with links to their websites and description of their products and services.
Of course, my book should also help you to get a quick start on it
Best Regards,
Sing Li
 
With a little knowledge, a cast iron skillet is non-stick and lasts a lifetime.
 
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