Re: Technologies for Consideration: Java ME ~ What's the deal?

[Ken Gilmer <ken buglabs net>]

Bartek,

  I was not aware of MicroEmulator, looks very cool.  And the usage  
scenarios definitely make sense.  This gets back to my original  
question: what functionality is Gnome Mobile looking for?  In my mind  
there are two primary paths:

1. J2ME (run phone apps, etc. on a Gnome Mobile device)
2. "Full" Java with deep integration into the platform

  Option 1 is very Java-centric, and 2 is more Gnome-centric.  Ross,  
can you provide feedback as to which option Gnome Mobile is most  
interested in?

thx
ken


On Sep 30, 2008, at 6:03 AM, Bartek Teodorczyk wrote:

> Hi,
>
> I'd like to show another option to support Java ME that is possible
> for GNOME Mobile using MicroEmulator.
>
> MicroEmulator [1] is Java ME implementation build on top of Java SE,
> it was also designed to run on less capable VMs like CLDC and CDC as
> well. Two years ago I prepared a proof of concept demo for Maemo
> platform [2] to demonstrate possible solution for Java ME applications
> running on Nokia tablets. In that example I combined Jam VM, GNU
> Classpath, SWT (my origin plan was to use GTK+ directly) and
> MicroEmulator.
>
> Here I try to do some weighing the pros and cons which may be in my
> opinion important for GNOME Mobile community.
>
> Pros:
> 1. License: LGPL and additionally large parts of project are Apache V2
> also dual licensed.
> 2. Small porting layer, it is about 15-20 classes that needs to be
> adapted to support GTK+ UI backend.
> 3. API's: JSR-118 (MIDP2), JSR-75 (File API), JSR-135 (partially),
> JSR-82 (together with BlueCove[3]), JSR-179 (together with OpenLAPI
> [4]).
> 4. Used by other important projects: Apache Harmony [5], Eclipse MTJ
> (previously EclipseME) [6], NetBeans IDE [7].
>
> Cons:
> 1. Not possible to get Sun TCK for open source Java ME implementation.
> 2. Not all API's are fully implemented yet, but general goal is to be
> MSA (JSR-148) compatible.
>
> Regards,
> Bartek
>
> [1] http://www.microemu.org/
> [2] http://www.microemu.org/maemo/
> [3] http://www.bluecove.org/
> [4] http://code.google.com/p/openlapi/
> [5] http://markmail.org/message/z7kiqk7wpd6vaina?q=apache+harmony 
> +microemulator
> [6] http://www.eclipse.org/projects/project-plan.php? 
> projectid=dsdp.mtj
> [7] http://wiki.netbeans.org/MobilitySolarisMacOSXSupport
>
> On Mon, Sep 29, 2008 at 11:43 PM, Ken Gilmer <ken buglabs net> wrote:
> > Hey Ross,
> > > Basically this means that we know that JavaME exists and is used  
> > > by some
> > > people, but there needs to be more research done to see if it  
> > > should be
> > > added as a recommended component, needs work to be better integrated
> > > into the GNOME Mobile platform, and so on.
> >
> > Got it.
> >
> > > This is where you probably know more than the rest of us: what is  
> > > the
> > > state of JavaME and GNOME Mobile integration?  (I'm very out of  
> > > touch
> > > with Java now, so bear with me)
> >
> > I'm CCing Robert Schuster from Jalimo [1], as he knows more than  
> > me on this,
> > but from my understanding there is a J2ME UI on GTK+ with midpath  
> > [2].  I
> > have not seen this myself but I think it has been used on the  
> > OpenMoko
> > device.
> >
> > > Is there an AWT or Swing implementation
> > > with a GTK+ backend?
> >
> > Yes, CACAO with GNU classpath supports GTK+ backend.  We have done  
> > some
> > preliminary work with our device with success [3].  JamVM should  
> > be able to
> > use classpath's GTK+ peers as well, however I haven't seen this.   
> > Currently
> > PhoneME only supports AWT with QT3 peers but there seems to be  
> > some activity
> > in a GTK+ port [4].  Bug is interested in this work as well.
> >
> > >  Are there usable DBus bindings?
> >
> > This is something I'll be looking into in coming weeks with dbus- 
> > java [5].
> >  My understanding is that it's at least possible with CACAO.
> >
> > > How about the
> > > rest of the platform such as GConf, GIO and so on?
> >
> > I haven't heard anything regarding either of these.  What  
> > components of the
> > platform would need Java bindings in order to become a part of  
> > Gnome Mobile?
> >
> > > Are some VMs better
> > > integrated than others, or do most open VMs these days all use
> > > Classpath?
> >
> > CACAO and JamVM use GNU Classpath but there is work under way to  
> > let them
> > use OpenJDK class libraries as well [6].  This is a very interesting
> > development.  PhoneME has it's own class library and is not able  
> > to use
> > others.  One key limitation of PhoneME is that it does not contain a
> > classpath exception.  There has also been some success in building  
> > OpenJDK
> > VM and classpath for ARM-based devices, although I think that's  
> > still in
> > early stages.  We have done some work [7] [8] in benchmarking  
> > various JVMs
> > on BUG but I wouldn't consider them complete, there is still some  
> > important
> > optimizations for CACAO that we haven't yet got worked out.
> >
> > In general I'd say that CACAO + GNU Classpath may in fact be a  
> > suitable
> > candidate for Gnome Mobile.
> >
> > > Answer these questions well Ken, and I may bring more  
> > > Laphroaig... ;)
> >
> > Uh oh...I think my liver still hates me for what happened on that  
> > boat
> > ride... :)
> >
> > cheers
> > ken
> >
> > [1] https://wiki.evolvis.org/jalimo/index.php/Main_Page
> > [2] http://midpath.thenesis.org/en/Start%20Page
> > [3] http://bugblogger.com/working-with-processing-on-bug-214/
> > [4] http://forums.java.net/jive/thread.jspa?messageID=275587&;
> > [5] http://dbus.freedesktop.org/doc/dbus-java/
> > [6] https://c1.complang.tuwien.ac.at/cacaowiki/OpenJDK
> > [7] http://bugblogger.com/java-vms-compared-160/
> > [8] http://bugblogger.com/java-vms-compared-ii-187/
> >
> >
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