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Learning Wireless Java
Qusay Mahmoud's text starts off with an introduction to the Java wireless platform, which includes learning about a good deal of four-letter abbreviations, among which are J2ME, CLDC, and MIDP. In fact, the first three chapters of the book offer a detailed explanation of what those platforms are, what they provide, and how they differ. For those who have done some J2ME programming before, this might seem a bit too detailed, but for beginners venturing into the wireless world these chapters offer helpful information on where to start, what software to download on your machine and what different software packages represent.
In fact, the author goes into detailed explanations of each software package that you need to download in order to start developing for J2ME, and most of the examples, such as setting the path and required system variables, provide step-by-step information for both Windows and Linux platforms.
You don't get to write your own MIDlet until chapter 4, and by that time you should be pretty comfortable with the terminology and abbreviations used throughout the book. Most of the examples in the early chapters of the book involve working with the command-line compiler, and only in section 4.2.6 does the author introduce the J2ME Wireless Toolkit IDE.
The rest of the chapters are concentrate heavily on the classes provided with the J2ME platform. Chapter 5 gives an overview of MIDP GUI programming with abundant examples and source code. Chapter 6 goes into MIDP event handling, where you learn about the ways users interact with their cellular phones and how all those button pushes are interpreted by the K Virtual Machine. Chapter 7 deals with networking issues (you actually get to write your own J2ME application for accessing the server), and Chapter 8 provides an introduction to database programming and storing non-volatile data on J2ME phones. While the application examples are definitely helpful, well-written and commented, I wish the author would spend more time discussing the hardware implementation of server-client communications, since it's not precisely clear how you can test your J2ME Internet-enabled applications on a real phone without calling your cellular operator and using up valuable minutes.
There is also a chapter on Palm OS programming, which was of limited value to me, and thus cannot be properly evaluated in this review. The appendices are very nice, and include the information that most of the developers would probably find very relevant. Appendices A, B, C, D, E, F and G include descriptions of such J2ME API libraries as java.io, java.lang, and java.util (even though the names are the same as J2EE versions, don't be tricked -- to save space, a lot of classes didn't make it to J2ME) as well as complete javax.microedition reference.
The book is a worthwhile read, easy to understand and follow if you have a good knowledge of Java behind you, and can definitely give you a good introduction to wireless development.
You can purchase Learning Wireless Java from bn.com. Slashdot welcomes readers' book reviews -- to submit yours, read the book review guidelines, then visit the submission page.
...Will this be useful in developing for TabletPCs?
Will the TabletPCs even support Java?
I only ask because these things are coming out SOON, wil work on wireless techonology, but won't be running an open-source OS. Remember, just because you like it so muc doesn't mean it's the reality of the situation, M$ does still dominate over 90% of the market.
Which brings me to my next point, why not do more open source development for windows, it's not like it would be impossible. Maybe if some really neat win32 based OSS projects became popular, it would really boost the image of OSS in general.
(BTW this was not supposed to be a troll, so if it comes across as such I'm sorry)
Linux is dead.
LU
TOO MANY ACRONYMS!!!! ;)
Teaching developers to develop good Java is hard, but it's easy to port good Java code to J2ME. I've done it dozens of times.
The only code I have to change is anything UI related. As long as the developers don't embed BL into the UI then we can use the same code for both the PDA and the desktop. Even the event model can be the same.
Just change the UI.
Oh, and one more thing: don't use every package in the book. Trying to have every jakarta library on a PDA get's a little harsh.
My $0.02 will always be worth more than your â0.02, so
I would like to start toying with J2ME and other phone api's however I have yet to come accross a single phone my company (telus) supports. Does anyone know of a wireless phone api list?
Oh, realy, then why won't this code work with J2ME ?
I don't know what code you have ported dozens of times, but strangely my code wasn't so 1:1. And I consider classes like InputStreams to be part of "Java" as in J2EE.This book assumes that reader [...] has programmed Java
:)
.sig is wrong, so what?)
basically, only James Gosling!
(yeah, my
667 The Neighbour of the Beast
I just started developing applications using J2ME for the Nokia 9290 Communicator and Voicestream GPRS enabled SmartPhones. There is one book by WIley "GPRS and 3G Wireless Applications" that is a perfect companion to this o'reily book. You will understand the underlying wireless network architechtures which is very important. GPRS devices are the future for developers, check em out http://www.racowireless.com/voicedataphones.htm
franco
Java = (-)
Wireless = (-)
Wireless(Java)= -(-) = +
this could be a Good Thing(tm).
(/sarcastic tone)
I want 2D games back.
The title of this book should be 'J2ME programming for devices' since there's nothing inherently 'wireless' about the material the author presents. There's no mention of programming for different wireless networks (GPRS, mobitex, flex...) or how to integrate w/existing popular wireless services (SMS).
it's not going to stop until you wise up, no it's not going to stop. so just give up.
Java, on anything other than sparc hardware, is utterly slow and bulky. Wireless (depending on what kind of wireless bluetooth, 802.11b, etc...) can be really quite slow.
Er, are you sure? If the network communication was fast, then the language would need to be fast, but if it's slow (as you say, but I disagree, BT is anything but slow) you would hve plenty of time to do your calculation before you had to do more network activity.
The whole point of running java is so apps can work on the multitude of new devices coming out.
Java = slow
Wireless = slow
Java + Wireless = I'de rather not think about it.
See my post here. This is bunkum.
If you have some magicly fast method of networking for these new devices (like, maybe we should like them together with co-ax), then I'm sure there's a few companies would like to hear about it.
Java + Wireless = I'de rather not think about it.
So *you'd* rather that cell phone and other wireless devices remained large monolithic bricks that had no more capabilities then dialing a phone number?
No thankee! I'll take application and network capable devices anyday to make my life easier.
-Brent
...and 10 times less expensive.
What are you talking about?
Java, on anything other than sparc hardware, is utterly slow and bulky.
How true this was in 1998. But after Java1.2 came out (we're on java 1.4 atm), its been compairable to C++.
I can't stand it when people talk about how slow java is. When was the last time you coded any java?
Good quote, too many chars. Seriously, the slashdot 120 char limit sucks!
If you think Java is too slow, you might still be in the mid 90s. Consider purchasing a time machine instead of a wireless PDA, and I think you'll find 2002 to be a more pleasant time than the 1996 that you've been marooned in.
I don't have a cell phone, but if I had one, I'd expect it to be good at being a cell phone, everything else they put in there is just useless.
Computers are everywhere, so why not just use one.
Anyway phones are everywhere also so I guess cell phone are useless too. I might change my mind when wireless broadband is a reality but untill then all the wireless hype is just that, hype.
Je t'aime Stéphanie
I attended a talk given by Sun, where they delved into the J2ME platform, and extolled its benefits. As I understand it, J2ME is a pared-down version of Java for use in mobile devices (what Sun demoed were cellphones and those Blackberry devices).
This would have been a great thing to have - about a year ago. A few select phones support J2ME at the current time (more on the way, I guess) - but what we're seeing, really, is a move towards Convergence cellphones, which are combining PDA's, cellphones, GPS, (you name it), into one tiny phone-shaped device.
With phones running PalmOS or M$-Whatever-its-called-this-week (and Linux, as soon as you nerds get around to it), I see no need for J2ME as a platform. You want software? Use the thousands of applications already written for Palm (and likewise for the M$ solution).
I like the idea of J2ME - I just think it is a day late and a dollar short. Sun is trying to get a handhold on a platform that is being outdated by the next generation of handheld devices. Sure, J2ME will probably run on the next generation of devices - but the user base and development community for those platforms is already in place.
--
Disclaimer: The above statement probably includes half-truths, because real truth is too complicated.
When was the last time you coded any java?
Well, yesterday. And even my coding itself was glacial because of the slowness of the development environment written in Java. Compare any Java IDE to any C++ or Visual Basic IDE and you'll understand.
IMHO, forcing your developers to use Java is plain torture.
Want a compiled language for rigorous development of large applications ? Go C++ and the STL.
Want an interpreted language for fast development (e.g. for dynamic websites) ? Go Perl or PHP.
Java is the worst of both. It's compiled so you need to trot the edit/compile/test cycle, but the language is poor and the execution is slow.
There is no reason why a cell phone or wireless device would communicate any slower with java on it than without. The protocols are all coded in embedded assembler or a PGA. Java or whatver other applications language will have nothing to do with data transmission rate.
Try JBuilder by borland.
And dynamic websites in a J2EE environment kicks the pants off Perl and PHP.
Nice bait, regardless.
Funny, what IDE were you using. I use JBuilder and it's as fast as a rabbit. Execution of Java is not slow. Only when you get in to swing do you have real problems, and in that case it's a library issue, not a language issue.
Hello there!!!
Did you ever run java? Compared to C, java is slow. Well kind of slow. About two times slower if you have a just in time compiler.
This doesn't matter if you have a GUI, because a GUI mostly waits for user input.
So, back to java phones. There are about 1000 games for java enabled phones out there, and because they use native methods they are fast enough.
The only slow thing is reading and writing rms files (mostly in flash memory). But this will also get better.
If you want to try it out get yourself a Nokia 6310i. This is the one I am currently working on.
While I understand and agree with some (not all of the comments) understand that J2ME is not targeted for just phones and PDA's. It extends beyond this space to include embedded systems, devices with no real display etc... While the book focus' on wireless devices, that is only one small area of J2ME. It terms of the comments on the slowness of the Java platform, I would suggest that you look at this again. Benchmarks have shown that Java's speed rivals that of a native language like C or C++. 90-99% of the slow Java programs out there are a result of programmers who have no clue as to what they are doing. They read Learn Java in 21 Days and boom they are Java programmers, don't think so. Just because you can read, doesn't mean you truely understand, comprehend and can apply the technology. Just my .02.
Wireless + Java = Fast
When using dedicated hardware Java is much faster on a wireless device that using a Virtual Machine on a Pentium machine, do your homework:
http://www.arm.com/aboutarm/4X8JCD/$File/ARM926
I'd like to know more about why you consider Java the "worst of both" (C++ vs. PHP). I've used all three, and my experience has been that all three have strengths and weaknesses.
What kind of software have you worked on with Java, C++, and PHP? In what environments? What type of hardware?
(This isn't a troll, BTW, I am always interested in alternative viewpoints. I often learn something interesting, and sometimes re-evaluate my own perspective.)
-Thomas
You might need to update your sig soon...
Slashdot's first reaction to VMware
Any slowness Java may have (actually it seems to run about the same speed as native programs on my computer) is more than made up for by the ease of programming. Compared to C and C++, Java is a piece of cake to program in. And unlike Perl, people can read and understand what you've written!
Maybe it's time to upgrade your 90 mhz Pentium?
In terms of processor speed I think wireless devices are only 2-3 years behind desktops. Java is just now starting to become fast enough for medium sized desktop applications (Try running JEdit on a high end machine and you will be impressed) so in 2-3 years java on wireless should be ok for just about anything.
Neil
all you need to program wireless java is an ir keyboard or a laptop you silly freaks... that is how easy it is.... ive been coding in java for 27 years ever since redhat was made , i am an expert.
i am actually quite surprised about some of the misconceptions here about j2me.
there's the usual java is slow mantra, which related to circa 1997 java maybe, but certainly not java today. there's the "but microsoft controls 90% of XXX", which of course forgets the fact that we're talking beyond the desktop here... etc,etc.
for a partial listing of reasons to use j2me:
http://www.blueboard.com/j2me/why.htm
btw, j2me is a PROVEN solution, with more than 23 MILLION handset clients already running it around the world (projected to more than a BILLION by 2004), and more than one hundred million java smart cards being used. it runs as the OS, on top of BREW, on top of SYMBIAN, and on top of LINUX, and on top of the lone WinCE phone.
more info:
Lurker's Guide to J2ME
Java schmava! This is very much like much ado about nothing. Basically an advertisement for a book, like this matters at all?
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Rhino fucks Penguin, news a eleven.
I've been programming in Java for over 5 years, and never noticed the wires. Hey, where'd those come from?
I never knew there were wires in Java.
Oh, well what do I know...
I'm a Java programmer about to be in the market for a cell phone... does anyone have any recommendations for nice Java enabled phone that would be well suited for hacking* on? Not major application development here, mostly just for screwing around....
Looking for a model that is
1) Reasonably inexpensive
2) Preferably supported by Sprint PCS (which looks like its going to be my carrier of choice.)
Any ideas?
* By hacking, of course I mean in the I-like-to-play-with-code sense, not in the evil, screw-with-other-peoples systems sense.
SpyDock: Scientific Python in a Docker container
I was in Japan for two years, and did extensive programming on the iAppli (Java that runs on iMode phones) and J2ME platforms. I even wrote a web browser for J2ME. You can see it all and get the source at http://www.ai.mit.edu/people/hqm/imode and also at sourceforge, look for the http://bearlib.sourceforge.net/ bearlib libraries.
have wires?
i knew they were up to something sneaky.
even when the euro is worth more than a dollar my $0.02 will be worth more than any 0.02 ^_^
No, this isn't flamebait, it's just a friendly jab at the other side of the pond.
My $0.02 will always be worth more than your â0.02, so
ya know, the only "dynamic websites" that consistently fail to come up in my browser are JSP/servlet pages.
and yes, i've coded java servlets, mod_perl, and PHP. these days, i don't even consdier using any of those: Zope kicks the pants off all of them.
Jython! that's fuckdiculous.
> I can't stand it when people talk about how slow
> java is. When was the last time you coded any
> java?
A few months ago, with 1.3 and 1.4... Swing stuff for the most part. If you hoestly think Java's speed is comparable to C++, you clearly haven't done much complex GUI stuff with Java.
Have you ever used Forte? Perfect example. There's just no excuse for the human eye being able to see popup menus being drawn on the screen running on an unloaded 1200Mhz athlon with 384 MB ram.
Many seasoned programmers I have known have jumped onto bandwagon of java, and got burnt here and there, so they are not so excited about java anymore. For clean style and programming you can use Jython, which is Java generator, but also integrates tightly with Java and its frameworks, including J2ME. I know C++, Perl, Python and Java, of them all I find python most clean and easy to work and maintain. So if I would have something to do and I can do it in Python(Jython) i'd use that...
How true this was in 1998. But after Java1.2 came out (we're on java 1.4 atm), its been compairable to C++.
:-)
Well, it's always been comparable. The results, however, seem to be changing