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Programming Wireless Devices With Java 2
As is characteristic of the titles I've seen from Sun's Java series, this book goes into great detail about architectural decisions, standards process, and philosophy underlying the new release. The first six chapters are given over to this discussion. This material is mostly great for experienced developers seeking a deeper understanding, occasionally so abstract as to be silly (as in the case of the Java washing machine and its downloadable stain-removing code), but likely to be of only secondary interest to new J2ME developers focused on coming up to speed.
What this book does best is comprehensive exposition of the J2ME APIs. There are chapters dedicated to the APIs for forms, graphics, games, sound, persistence, and networking, with code samples offered in most cases, and a Java Almanac-style reference to all J2ME-specific classes and interfaces is provided as an appendix. Features that are new to the J2ME second edition are clearly identified.
The remainder of the book constitutes a detailed discussion of the new technologies for event-driven launch, application security, and over-the-air deployment, perhaps the most potentially confusing of which is event-driven application launch. While the book explains the new technology well, it doesn't address how it will be introduced by network operators, or how it might interact with or replace similar existing proprietary technologies such as Sprint's MUGlets.
Another subject that is not dealt with here that will soon be relevant to developers for any particular J2ME-supporting network is that of optional packages (OPs) - features to be supported at the option of particular device vendors and/or network service providers. It is fairly clear that, going forward, the wireless network infrastructure and its supported features will be an integral part of the J2ME platform that will have to be taken into account by developers, and books which fail to discuss popular and commonly adopted OPs will be of limited usefulness (you'd think that Sun would know that after all that rhetoric about the network being the computer). In general, a book of this sort would benefit from the participation of network operators, as it does from that of device manufacturers Nokia and Motorola.
All the code samples and background on architecture notwithstanding, this book is clearly targeted at experienced Java programmers, not handheld device programmers working in other technologies. If you don't already know Java, this book will not teach you. There is also nothing said here about selection, configuration, or use of development tools; readers who are not already adept at the use of J2ME development tools, including the Wireless Tool Kit (WTK), should not expect to acquire that knowledge from this book. (People who need help in this area may want to consider Jonathan Knudsen's Wireless Java or Kim Topley's J2ME in a Nutshell.)
Keeping the aforementioned caveats in mind, this is an excellent introduction to and reference on the new release of J2ME.
You can purchase Programming Wireless Devices with the Java 2 Platform, Micro Edition, 2ed. from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
I shouldn't need a book to create Java applications for a mobile device. I should need a two page cheat-sheet that maps "mobile" concepts to core Java/Swing concepts.
BTW, I did finally get my Palm program working by using Waba (http://www.wabasoft.com), which I thought was far superior to what Sun was putting out.
I've been involved with wireless programming and Java since late 90's. So far Java hasn't lived up to its promises. Sure, you can do nice games on mobile phones, but real programming is a joke.
For an example six months ago I had to do a little program that sent data through Nokia 9210's irDa port. API seemed to support it, so I made a program that used the irDA. Unfortunately the program never could open the irDa port. After days of research I finally found out that Nokia had NEVER implemented the irDa port correctly to the library that Java used. They had a typo in the port name, but nobody seemed to care about 'a minor flaw' at Nokia. The bug had been there for years and there was no way you could use irDa with Java in Nokia 9210(i).
After that I just switched to the C++ and everything worked perfectly.
The problem with mobile phones and Java generally is that if hardware interface is not implemented correctly, you can do nothing about it. Can you imagine yourself coding hundreds of hours a Java program and finally realising that the API hasn't been yet implemented fully and the program can never run. Ok, maybe not never, but would you like to wait years before you get fully implemented API?
Whats to believe?
What's the fastest runtime for Python? Can it translate to C code?
The fastest Java runtimes are approaching C++/Fortran speeds.
My personal quest has been for a productive, portable language that's efficient enough for high-end gaming applications. C++ isn't too productive, but GC pauses and portability (consoles) are still issues for Java games. Gcj looks interesting - with it you can disable bounds checking and GC (not a problem if you use mostly static objects).
One point of synergy between Python and Java is Jython - Python that compiles to Java byte code. Perhaps the JVM is the fastest Python runtime... ;-)
Galileo: "The Earth revolves around the Sun!"
Score: -1 100% Flamebait
This weekend, I took the time to review two competing programs for your computer: J2ME, and WinME.
First off, WinME. WinME is what computer people call an "Operation System", which means it is a program that can perform operations on a computer. What I really liked about WinME over its predecessor, MacOS9, is that the menu is on the bottom of the screen, there are great screen savers like a Star Wars -ish one where stars fly across your screen, and it supports a mouse with more than one button. Other noteworthy features of WinME was that I can sign up for AOL right off of the homepage, just by double-clicking on the little AOL picture. Neat!
Now, here is where the story gets good. J2ME is just like WinME in many ways - Microsoft designs them that way so you don't have to relearn your computer everytime you "install" a new "operation system" (see, this isn't so hard now, is it?). The only thing I didn't quite understand was that WinME comes on a CD-Ram, and J2ME comes on a cellular phone. Now, I am usually really savvy with computers, but I still just can't figure out how to get J2ME off of my cell phone and onto my PC. This is important to me, because I really want to "upgrade" my PC from MacOS9, which was an earlier version of WinME/J2ME that just isn't as good as those two.
Nevertheless, I think that Microsoft is doing a tremendous job with their entire 'ME' series of operation systems, and I hope you agree!
Compared to the other demands on medium/high end mobile (camera, bluetooth, the GSM/CDMA network itself), Java doesn't have that much implication for battery performance- provided it has a decent software implementation or some form of HW acceleration.
Some phones have better Java technology than others however.
Which is better depends on what you need.
Ita erat quando hic adveni.
Bloody hell.. lets see there are nearly 100 mobile phones that support J2ME, there are over 100 million sold in the last 12 months world wide and Nokia in ONE QUARTER ALONE sold over 800,000 of the high end smart phones.
Low end phones like the 6310i have been J2ME phones for around a year now. And now almost ALL phones released in Europe and Asia are J2ME enabled.
Basically you know zip, zero, nada about Mobile Applications.
This isn't new, this is way over 12 months old and represents already a multi-million dollar industry in selling J2ME applications to consumers.
An Eye for an Eye will make the whole world blind - Gandhi
There are only about 125 classes in the entire MIDP specification, and alot of these are things like Integer and IllegalStateException. When you get down to the meat of it, there's maybe a couple dozen classes that you really need to understand.
I find MIDP to be very simple and easy to use. Maybe it helps to be a Java progammer and understand the Java way of doing things, but I've built a few J2ME applications and I've been amazed at how little time they took to create, and how well the finished product performed.
Yes and no. Java's OO structure (IMHO) is much clearer and strictly defined. Java also runs on micro-devices (what this review is about) whereas Python does not. There are those people that will also argue that Java's performance benchmarks can also beat out Python. Python's a great language, and I've been impressed with it, but then again, C# is much the same. Java is the king of that hill, and it will take some serious work to knock it off.
--My other sig is a ferrari.
Um, did you or any of the asshat moderators bother to read my post or did you just interpolate from the highlighted word?
My point is that without the APIs encapsulating the hardware interfaces you can't write serious programs in Java, not that you shouldn't. How is your mobile phone going to interact with that Exchange server if you can't even use the phone's network interface? If the J2ME API is not fully implemented, then you're trapped in a little mobile jail.
I was arguing that industry has shown itself unable to properly implement APIs for high-level languages, so therefore volunteers need to implement them. As a result, someone needs to know the low-level language because Java can't be used to write its own APIs. Java can be used for serious programs, but only after someone else does some programming in a lower-level language.