Raspberry Pi Java & NetRexx

[Bruce Skelly]

Hi,

I know that there was a problem with the version of Java that was installed on the Raspberry Pi.  I installed Adafruit's Occidentalis_v02 distribution that was based on Raspbian Wheezy.

If I understand the problem correctly the original version of Java in the distribution used software floating point emulation.  That, if I understand naming conventions correctly, is no longer the case.

This is my current /usr/lib/jvm directory:
lrwxrwxrwx 1 root root   20 Sep 25 17:55 java-1.7.0-openjdk-armhf -> java-7-openjdk-armhf
drwxr-xr-x 5 root root 4096 Mar  1 12:23 java-6-openjdk-armhf
drwxr-xr-x 8 root root 4096 Mar  1 12:23 java-7-openjdk-armhf
drwxr-xr-x 3 root root 4096 Mar  1 12:24 java-7-openjdk-common

Notice that both my java6 ad java7 appear to be armhf, i.e. hardware floating point.

My questions to the group are:
1. Am I reading this correctly?
2. Is there a piece of code I could compile and run to show that this is working correctly?

I have installed NetRexx V3.01, and using the ejc, have compiled and executed trivial NetRexx code.

Thanks,

Bruce

[Fernando Cassia-2]

On Fri, Mar 1, 2013 at 9:07 PM, Bruce Skelly <[hidden email]> wrote:
> I know that there was a problem with the version of Java that was installed
> on the Raspberry Pi.  I installed Adafruit's Occidentalis_v02 distribution
> that was based on Raspbian Wheezy.
>
> If I understand the problem correctly the original version of Java in the
> distribution used software floating point emulation.  That, if I understand
> naming conventions correctly, is no longer the case

Hi Bruce!

I haven´t played with the RasPi, but I plan to do so when I get one :).

However, it is not clear by reading your email what the problem was, if any.
In other words, if the version of OpenJDK shipped with that particular
distro used floating point emulation, it´d have been a bit slower for
math operations, but besides that performance ´problem´ code would
still run ok.

In any case, you might want to check out the Pi4J project, to ask
questions and also meet other Java devs working with the RasPi.

http://pi4j.com/

Not sure if I have helped at all, but just thinking aloud.
FC

PS: Another place to learn about java on Arm and the
intrincacies-differences between different OpenJDK builds and ARM
optimization is
http://labb.zafena.se/?p=514
For example, I know there are different optimizations in place in
Debian´s OpenJDK for ARM that make it much faster than the OpenJDK in
other ARM Linux distros. I don´t remember the specifics but it had to
do with ARM compiling options...
--
During times of Universal Deceit, telling the truth becomes a revolutionary act
Durante épocas de Engaño Universal, decir la verdad se convierte en un
Acto Revolucionario
- George Orwell

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[Fernando Cassia-2]

On Fri, Mar 1, 2013 at 9:07 PM, Bruce Skelly <[hidden email]> wrote:
>
> If I understand the problem correctly the original version of Java in the
> distribution used software floating point emulation.  That, if I understand
> naming conventions correctly, is no longer the case.

By the way, slighly related to your post.... there´s ongoing work to
add properties to OpenJDK to let it identify the different ARM CPUs so
from the software side it could detect and optimize what ARM code to
use.

http://mail.openjdk.java.net/pipermail/porters-dev/2013-January/000426.html

So, if I understand things corretly, things will be much smoother for
OpenJDK in ARM-land going forward...

FC
PS: coming from x86-land and not having to deal with these issues, all
this endian and floating point stuff is way above my comfort zone, so
if I say something stupid please let me know ;)


--
During times of Universal Deceit, telling the truth becomes a revolutionary act
Durante épocas de Engaño Universal, decir la verdad se convierte en un
Acto Revolucionario
- George Orwell

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[Fernando Cassia-2]

On Fri, Mar 1, 2013 at 9:35 PM, Fernando Cassia <[hidden email]> wrote:
> Not sure if I have helped at all, but just thinking aloud.

Bruce,

as an addition to my original reply:
btw: found the one I saw a week or two ago on Twitter.... I think
you´ll like this:

http://www.trimslice.com/forum/viewtopic.php?f=48&t=1214

"Setup instructions on how to combine the hardfloat Oracle JDK 8 EA
JVM armhf in combination with the OpenJDK 7 classes to get access to
Swing/AWT using the hardfloat jvm."

This is said to offer the best performance on the RasPi.
For further questions I suggest you reach out xranby
https://twitter.com/xranby

(yes, Alan Sampson, Twitter, you might have heard of it ;) -internal
joke, Bruce-
FC

--
During times of Universal Deceit, telling the truth becomes a revolutionary act
- George Orwell

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[Bruce Skelly]

This was announced today.

http://www.raspberrypi.org/archives/4920

So Oracle Java 7 JDK with hard float is now available for the Raspberry Pi running Raspbian.

sudo apt-get update && sudo apt-get install oracle-java7-jdk

Bruce

[Tom Maynard]

Oracle Java 7 JDK with hard float is now available for the Raspberry Pi
running Raspbian.

Thank you for this news, Bruce!   I've been running Java 8 on mine, but for
a number of reasons, I prefer Java 7.  It also means that I can have the
same release on the RasPi as I have on the BeagleBone Black.  Sweet.

A piece of very good news, indeed.

Tom.


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