Win a copy of Think Java: How to Think Like a Computer Scientist this week in the Java in General forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

J2ME development : CLDC vs CDC

 
Dorothy Taylor
Ranch Hand
Posts: 104
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi All

I am new to J2ME and there are a couple of things that I would want to know.

The PDA that I am using is MC70 EDA. I want to know if I should use the javax.microedition.* package to develop my application on it or can I just use the JVM AWT (java.awt.*) package(by installing CrEme)

Please guide as I really do not whether we should use CLDC or CDC for application development on PDA'a


Regards
Dorothy
 
Tim Holloway
Saloon Keeper
Pie
Posts: 18152
52
Android Eclipse IDE Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
The choice of which JME profile you program to is determined by what the manufacturer includes with the device.

Unfortunately, this is a Windows Mobile unit, so it may not include Java support at all.
 
Dorothy Taylor
Ranch Hand
Posts: 104
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Well, my understanding is that the PDA which I have, since it being a Pocket PC, I should be using CDC.

I hope this is how it is supposed to be. I mean if it was a PalmOS device, maybe I should have gone for CLDC but not in case of Pocket PC's.
Is this right?
 
Tim Holloway
Saloon Keeper
Pie
Posts: 18152
52
Android Eclipse IDE Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
No, the problem is that Microsoft doesn't love Java and hasn't loved Java ever since they lost the lawsuit with Sun over their attempt to hijack the standard.

So Java support doesn't come with Windows Mobile.

You'll only have Java if the manufacturer added it on top of Windows Mobile, and from what I can see from the spec sheet, Motorola didn't do that. So the only way you can do Java at all on that device is if you can find and install a third-party JVM like the IBM J9 (WebSphere Anywhere) JVM. In which case, you'll get whatever profile that JVM supports, but it almost certainly won't have the ability to access the device's telephone software, its address book, or items external to the base profile such as Bluetooth or GPS.
 
Dorothy Taylor
Ranch Hand
Posts: 104
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks Tim. This information is really useful. Couple of questions though:

1. We have installed Creme on this PDA, to have the JVM. As you have suggested that a third party JVM needs to be installed like J9, therefore, is the choice of going with Creme correct?

2. Are there any other options also available like Creme and J9? How should we decide which one to choose?

3. Motorola provides an eclipse based IDE (we can also use Netbeans 6.5) and Emulator toolkit for testing on Motorola devices, reference URL : http://developer.motorola.com/technologies/java/. However, this is only for CLDC-MIDP applications and not CDC development. Is there any IDE available for CDC development with emulator for MC70 devices?

4. Which would be the right choice for development - AWT or Spring?


Thanks and Regards
Dorothy
 
Tim Holloway
Saloon Keeper
Pie
Posts: 18152
52
Android Eclipse IDE Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I hadn't heard of Creme. I'll have to look into it. I suspect my next smartphone is going to be an Android unit, though.

As far as GUI frameworks go, it depends. Modern-day mobile devices are powerful enough to support AWT and Swing, but the original J2ME framework wasn't that expansive, so a completely different UI framework was created for the CDC and CLDC: javax.lcdui.
 
Tim Holloway
Saloon Keeper
Pie
Posts: 18152
52
Android Eclipse IDE Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Update: I looked at some info on J9 and Creme (or CrEme, if you like absurd capitalization).

Both these vms appear to be CDC implementations. J9 supports AWT and SWT, but not Swing. Creme supports something called Tiny AWT and Swing, as well as SWT. I think that outside of Truffle AWT, you'll probably have to install additional packages to get the more extensive UI frameworks, but I'm not sure.
 
Dorothy Taylor
Ranch Hand
Posts: 104
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
so, can we say that Swing should be the right choice for development using Creme? I mean can we opt for Swing rather than AWT?
 
Tim Holloway
Saloon Keeper
Pie
Posts: 18152
52
Android Eclipse IDE Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Originally posted by Dorothy Taylor:
so, can we say that Swing should be the right choice for development using Creme? I mean can we opt for Swing rather than AWT?


So they claim.
 
mads johansen
Greenhorn
Posts: 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Please take a look at this free and opensource J2ME for windows mobile.

http://www2s.biglobe.ne.jp/~dat/java/project/jvm/index_en.html
 
Tim Holloway
Saloon Keeper
Pie
Posts: 18152
52
Android Eclipse IDE Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Mads, I appreciate you passing on this information, but http://faq.javaranch.com/java/DontWakeTheZombies

It's OK to start your own topic if you have something to contribute. Of course if we think you're only in it for the money, we reserve the right to move it to out Blatant Advertising forum, but we do encourage people to let us know if they have information that may benefit the community.
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic