Which Java JRE?

Rafael Campos methril at gmail.com
Sat Dec 5 15:27:26 CET 2009


On Wed, Dec 2, 2009 at 1:12 PM, Arigead <captain.deadly at gmail.com> wrote:
> Bernd Pru"nster wrote:
>> Martin Jansa wrote:
>>> On Thu, Nov 26, 2009 at 03:06:35PM +0000, Arigead wrote:
>>>> Hello all,
>>>>     I'm working on a project and I think it'd be cool as to show off the
>>>> project's work on a phone. The OpenMoko phone ;-)
>>>> Unfortunately the project is implemented in Java, which I'm no fan of on
>>>> anything but a web server or browser but that's a discussion for another
>>>> day.
>>>> I tried our system, which is running in an OSGi Container, on Jamvm on
>>>> the OpenMoko. It works but it sucks up 95% of the CPU when it's idle.
>>>> Not Good! I tried the same on my eeePC and with Sun's JRE our system
>>>> uses 1% of CPU whilst JamVM on the eeePC uses 40%. Obviously JamVM does
>>>> not suit our system.
>>> No idea if it would be better, but have you tried cacao? Its in shr-feeds now again.
>> This is really weird!
>> I wrtoe one more or less serious app in java for the freerunner and a
>> couple of test apps and jamvm had avery fast startup, but was not as
>> compatible as cacao, but easier to use and did not require that much
>> ressources.
>> which distro are you using? which feed are you using to install jamvm
>> (dunno if still true but there used to be a difference depending on
>> where you installed it from).
> Sorry I've been a bit busy on stuff and only now catching up here on the
> list.
> I'm using the latest classpath 0.98 and Jamvm 1.5.3  I can't remember
> the specifics at the moment but there was some feature of Java 6 that
> our system's code was using which required JamVM 1.5.3 which in turn
> required Classpath 0.98. I just used a OE recipe for those and build
> them for the OpenMoko.
> I tried the Cacao JRE on my eeePC and it soaked up resources as well so
> I never even bothered to build it for the phone. Obviously something in
> our Java System, mabe knophlerfish is not streamlined in these JRE's.
> There is a Huge difference in running our system in a SUN JRE (1% CPU
> According top) and other Jre's
> I'm working now on the eeePC to see can I reduce this 40% on Jamvm. When
> I get time actually I'm now trying to connect to an AdHoc wifi network
> form the FreeRunner.
> Thanks for the clarification on the ARM front. I don't think Sun have a
> JRE for an ARM 4, no surprise really ;-) Things would be too easy.
> _______________________________________________
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> community at lists.openmoko.org
> http://lists.openmoko.org/mailman/listinfo/community
I think that OpenJDK has some JRE machines running on ARM. It's no
receipe in OE yet, but i tested a GUI in a OE machine and worked fine.
I didn't test the load of the CPU, but i could tell that some JREs are

I hope to post some of this in OE repos, and get a OpenJava JRE machine :)

Rafael Campos
o0 Methril 0o

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