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Cell Phones and Services for Java Developers?
Xi asks: "My cell phone recently died, forcing me to start looking for another cell/provider. I want one which will allow me to do some simple client/server Java programming but I'm perplexed by the array of choices. Some providers let you pay to download Java apps but do they let you create your own? Several providers can utilize phones on which Java runs but do they have to host some sort of software on their side? For instance can I use a Java enabled phone with T-mobile? Nokia, Nextel, Motorola (who shipped a Developer's CD with my October copy of Java Developers Journal) and its recent acquisition, AT&T, Sprint (new pricing), and others are all claiming Java this and Java that but what am I really 'getting' and what are fellow Slashdot-reading Java developers really using?"
Why would you want Java on a phone? Its already a pain in the ass that so many websites require it. If you really want to learn java I suggest doing it on a pc. If you really want a flash trendy cell phone, get one of those ones with color screens and cameras that let you send pics and sounds to your mates.
AFAIK, the network operator has little (if any) to do with the usage of Java (J2ME) on your phone.
You can always write you own programs, and copy them to your phone. You can (with some trickery, I'm sure) post them on the Web (WAP?) and let other people download them to their phones.
The client/server part of J2ME is more-or-less URL-based HTTP/TCP transfers. I assume you're talking about GPRS (G2.5) phones: in that case, to use the networking from J2ME you just need that your phone provider allows you to connect to the Internet (as opposed to just their local network) via GPRS.
The above is based on Nokia informations, Sun's J2ME API reference, and European networks.
dakkar - mobilis in mobile
There are more, and if you look at the recently released phones - J2ME seems to be there in most devices (excluding the cheapest model-range). Get the J2ME toolkit (this one for windows), the page will tell what else (java related) you also need.
Some operators might have for some odd reason disabled downloading some J2ME content although I don't know any such operators. Anyway, the operator choice should not affect your ability to start developing your own J2ME applications.
A friend of mine just got the new top of the line Sprint Vision phone and in the debug menu is a Java app launcher. I've been commissioned to see if I can write a SSH client for it. It can do SHTTP so I dont see a problem. Check www.a500hacking.com for more.
Viva La Revolucion! Buy a Mac!
Checkout alt.cellular.* for more info.
If Chaos Theory has taught us anything, it's that we must kill all the butterflies.
I suggest you check out Sun's Wireless Site. There are a ton of articles, documentation, and code examples from which to learn.
How about the Blackberry 5810? It runs J2ME and you can download an emulator and SDK from their developer's web site.
Sprint's implementation is open and accessible. You can write plain MIDP1.0 apps and download them to the phone from any webserver. It also supports extension API's for sound and connectors for https, ssl & sockets to do virtually any type of network based stuff.
"I have been around the world and found that only stupid people are breeding" -- Harvey Danger
I was in a similar situation, I really wanted to program java apps on my cellphone (Dont ask me Y, im just a geek). Nextel was the only company in my area offering java-enabled phones, so I picked up one of their i85s models. Its a really nice phone, and the Java stuff works sweet on it.
.jad file on the web and download the app, not Motorola.
The only problem is getting the apps onto the phone. Motorola is being a nazi about controling the ability to distribute apps, if you arent in their developers program you can only download offical apps through their propritary download program. As far as getting into the development program, I have no idea, Ive applied for it through my work and as a student to no avial. Im even one of the few people running some J2ME projects on sourceforge.
Im told other phones have the ability to simply point themselves at a
I use a Nokia 7650 (which replaced a Nokia 6310). This phone is fully J2ME (in fact, I use a Java app to browse HTML pages coz the internal WAP browser doesn't cut it).
(Disclaimer: My J2ME experience on cellphones is limited to the Nokia 7650 and the 6310i. Everything stated for here applies only to those platforms)
When you download a J2ME application, 2 things need to be taken in to account. 1) Does the app use a resolution that will fit on your screen (same size or smaller that is). 2) Do you have enough storage space for it?
Once you've answered those, there is no other hassles with a J2ME application (short of any programming or compatibility issues). Just install it and run it from the menu.
You can download the J2ME applications from anywhere you choose. Download them to your PC and then transfer them across (via irda or bluetooth in my case), or download them directly from the net to the phone. With the Nokia 7650 you can even get them via POP3/IMAPv4 if you wanted.
Anyway.... J2ME applications reside on the phone, run on the phone, and are controlled by you and the settings of your phone. Once you've downloaded the application, the Telco/ISP has no control over the application itself (outside of licensing issues).
You do not need the Telco/ISP to write your own J2ME applications and run them on your J2ME capable phone.
I've got a Nokia 3410, which is MIDP1.0 compliant, and this book from O'Reilly which i found helpful. I'm using the J2ME toolkit to help package and test the apps I write (it has an emulator).
To get them onto my phone is a moderate pain. I have apache running on my machine, and added the following into mime.types:
text/vnd.sun.j2me.app-descriptor jad
application/java-archive jar
oops...
and then bookmark 'http:///App.jad' in my phone and then download it over WAP.