GeeCON Prague 2014*
The moose likes Java Micro Edition and the fly likes new to J2ME, a few quick questions... Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


JavaRanch » Java Forums » Mobile » Java Micro Edition
Bookmark "new to J2ME, a few quick questions..." Watch "new to J2ME, a few quick questions..." New topic
Author

new to J2ME, a few quick questions...

Dan Maples
Ranch Hand

Joined: Jun 21, 2004
Posts: 153
Hey everybody I'm starting to try to learn J2ME, I tried to dive into it pretty quickly and got myself confused. I have a few questions that I can't find the answers for that I'm sure somebody can help with.

1)Can J2ME applications run on a pc? (without the cell phone emulator) and if so what (if anything) do you need to run it?
2)Do you need anything special to run J2ME apps on a PDA? Or is it the same as apps for a cell phone?
3)Can one app run on all PDA's or does it have to be altered for palm OS vs. Pocket PC etc.
4)How do J2ME profiles work?
5)Are the collection classes supported in J2ME?
6)Are there any XML parsers available for J2ME?
7)Does J2ME support Applets?
8)Does J2ME have any support for JSP containers?



Thanks in advance for all the help!!!

[edit: added questions 7&8]
[ July 26, 2005: Message edited by: Dan Maples ]

-Dan
William Frantz
Ranch Hand

Joined: Dec 08, 2004
Posts: 102
1)Can J2ME applications run on a pc? (without the cell phone emulator) and if so what (if anything) do you need to run it?

Yes, they run on a PC. You need to use the emulator but you don't have to use one that looks like a cell phone. With the Sun SDK you can create your own emulator using any image you want.

2)Do you need anything special to run J2ME apps on a PDA? Or is it the same as apps for a cell phone?

You need a Java Virtual Machine. Many (most?) PDAs do not include a JVM from the factory. You may have to install one. Yes, the same app that runs on your cell phone should run on your PDA if it supports the same profile.

3)Can one app run on all PDA's or does it have to be altered for palm OS vs. Pocket PC etc.

"Write once, run everywhere" is the Java motto. The reality is that you will probably want to customize each version to take advantage of different display sizes or keyboard layouts. You will also find numerous bugs in JVMs that force you to create device specific work-arounds.

4)How do J2ME profiles work?

Devices implement a profile like MIDP 1.0 or MIDP 2.0. Each profile consists of a different set of JVM capabilities and APIs. You need to write your application using the APIs supported by your target JVM's profile.

5)Are the collection classes supported in J2ME?

Basic collection classes from java.util are available such as Stack, Vector, and Hashtable. You also get Enumeration but not Iterator.

6)Are there any XML parsers available for J2ME?

Yes, kXML is an open source project (www.kxml.org) but I highly recommend you avoid trying to do things like XML parsing in a MIDlet.

7)Does J2ME support Applets?

No.

8)Does J2ME have any support for JSP containers?

No.
Dan Maples
Ranch Hand

Joined: Jun 21, 2004
Posts: 153
Thanks William! you have been most helpful!!!
Billy Tsai
Ranch Hand

Joined: May 23, 2003
Posts: 1304
do the developers need the technical capabilities in low level languages such as assembly, C, C++ and OS concepts in addion to J2ME to be able to write mobile phone softwares for phones such as nokia, motorola, xcute, benq etc....
?


BEA 8.1 Certified Administrator, IBM Certified Solution Developer For XML 1.1 and Related Technologies, SCJP, SCWCD, SCBCD, SCDJWS, SCJD, SCEA,
Oracle Certified Master Java EE 5 Enterprise Architect
Dan Maples
Ranch Hand

Joined: Jun 21, 2004
Posts: 153
One more quick question I came up with:
What are the associated technologies, Java libraries, and JVM�s for each profile?

Thanks!
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: new to J2ME, a few quick questions...