developing for cellphones and PDA with GCJ and GIJ

[Natale Vinto <ebballon at interfree dot it>]

Hi all,
I was looking for a way to yse GCJ also for mobile developing with Java and 
then I've done some try that I would report hoping could be useful.

I tried to use develop for cellphones using J2ME framework (java 2 
microedition) from Sun with GCJ. Compiling it's ok, the

gcj -C --classpath .:(J2ME JARS) Sources.java sources1.java etc

make a good .class file (for JDK -target or -source is preferred) but , 
because the J2ME developing process  is:

-compiling OK
-preverifying NO
-testing on Desktop ?OK

the preverify is not supported cause there is Sun binary tool, preverify, that 
preverify and prepare classes to be ready for run.

The testing could be done with an opensource sourceforge project
microemulator.sf.net ,is a J2ME apps emulator and it is realeased in SWT too, 
so it could be used compiling it or using GIJ.

About PDA I found it working with the SuperWaba framework 
(www.superwaba.com.br), that is a VM for WinCE,PalmOS and SymbianOS 7.0 .
The superwaba developing process is:

-compiling OK
-making SuperWaba compatile binaries ?OK
-testing on Desktop OK

the compiling could be easily done with GCJ , for example

gcj --classpath .:$SUPERWABA_ROOT:/lib/SuperWabaTools.jar:
$SUPERWABA_ROOT/lib/SuperWaba.jar -C Source.java

where $SUPERWABA_ROOT is the dir where SuperWaba is installed

This make a .class compatible where JDK 1.5 faults cause the javac -target 1.1 
is not possible with the 1.5 version.

The to make SW binaries(PDB , PRC, EXE, CAB) are used some JARs from SuperWaba 
framework, so they can be created in this way for example 

java -classpath 
$SUPERWABA_ROOT/lib/SuperWabaTools.jar -Dsdk.root="$SUPERWABA_ROOT" 
superwaba.tools.Warp c ClassName

java -classpath $SUPERWABA_ROOT/lib/SuperWabaTools.jar:
$SUPERWABA_ROOT/lib/SuperWaba.jar -Dsdk.root="$SUPERWABA_ROOT" 
superwaba.tools.Exegen /m /v 1.0 /t ClassName /p ClassName /e ClassName

this make PDB,PRC(palm os binary) and EXE(wince binary)

I tried to use GIJ for this but I've got some errors..anyway GIJ could be used 
for testing on Desktop superwaba application as applet. In fact for example

gij --classpath .:$SUPERWABA_ROOT/lib/SuperWaba.jar waba.applet.Applet /w 
240 /h 291 /uiStyle WinCE /bpp 8 /scale 1 ClassName

this emulate a WinCE/Pocket PC device on Desktop with the application compiled 
before with GCJ.

This is my experience with mobile developing with GCJ, I know isn't much but I 
hope could be useful to you too.

Regards




-- 
Natale Vinto @ Blues-Man
http://www.gotext.org