Java


Mookmac

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I know that someone ported Java for the GP2X but to use it you needed the nessecary files also on your SD. But was wondering whether Pandora will support it out the box? Perhaps have all the nessecary files pre-installed so that if I was to make a java app for Pandora I'd know that everyone could use it without worrying about whether they'd copied all the supporting files accross.
 
Yes - but do any of the open source JVMs use it? I was skimming the Wikipedia article on ARM chips, and I believe it said that they are fairly tight fisted about who they let know how on earth Jazelle actually works...

Of course, it's Wikipedia, and I could be missing the point some, but the tone was pessimistic re: free implementations of Jazelle support...
 
Heh, java hardly gets any love in the hard core open source community. We either like our languages to be either fully compiled or fully interpreted. I wonder what could be done with that "java" execution unit ?
 
atomicthumbs said:
This might work well. Doesn't the OMAP3430 have Jazelle Java native bytecode execution buzzword support?
Cortex-A8 does not implement full Jazelle; here is the quote from the TRM:

QUOTE
The Cortex-A8 processor provides a trivial implementation of the Jazelle Extension. This means that the processor does not accelerate the execution of any bytecodes, and all bytecodes are executed by software routines.
 
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:( Why would ARM state that they have " Jazelle® RCT (Runtime Compilation Target) technology for efficient support of ahead-of-time and just-in-time compilation of Java and other bytecode languages." if they don't support it in hardware. Anyone can do java in software. I can compile java on my laptop. Should I stick a Jazelle sticker on it too?
 
icurafu said:
:( Why would ARM state that they have " Jazelle® RCT (Runtime Compilation Target) technology for efficient support of ahead-of-time and just-in-time compilation of Java and other bytecode languages." if they don't support it in hardware. Anyone can do java in software. I can compile java on my laptop. Should I stick a Jazelle sticker on it too?
Jazelle RCT is *not* Jazelle DBX, read this document to understand the difference Jazelle RCT

To sum up, Jazelle RCT is an helper for JIT :)
 
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Julius said:
Didn't SUN recently release the original Java RE etc as free software (GPL with classpath excerption)?

Oh and maybe this free java based STEAM alternative (linux compatible) could make for a nice content download system for the Pandora:
http://sourceforge.net/projects/opencds
http://openfrag.org/forum/viewthread/1382


Linux already has many different content delivery systems, Some distributions (Debian/Ubuntu) manage EVERY single piece of software and library and updates via a package manager which connects to an extensive online repository. Except for Java that is. At least a year or so back when i tried it and had to manually install it. There doesn't seem to be much interest for java in linux, not on the X86 platform at least.

Did I hear the Pandora would be Debian(ARM) based? If so they'll likely use the existing package/content systems which work exceptionally well. In my opinion that's by far the best thing about Debian and it's derivatives.
 
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Zarneth said:
There doesn't seem to be much interest for java in linux, not on the X86 platform at least.
It was true until recently, because Java was not open source. There is no doubt that with the decision of Sun to open it, it will change. More and more open-source applications will be written in Java, and Java will be packaged with all linux distributions in the future.
 
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I'm hoping Python will be supported well myself. I personally find the syntax infinitely easier, faster and less confusing than Java. Python appears to be reasonably commonly used in linux too.
 
java doesn't get much love on low end machines -- its slow for writing games usually (but not always, and obviously depends on the type of game and how much JNI stuff you do..), and is less portable. (Java has been marketted as being mega portable.. its not. Once java ids ported, you tend to get the java platform which is a huge win, but java itself.. not so much. Most JVMs are written in C, so by definition C is available in more locations than java.)

jeff
 
skeezix said:
java doesn't get much love on low end machines -- its slow for writing games usually (but not always, and obviously depends on the type of game and how much JNI stuff you do..), and is less portable. (Java has been marketted as being mega portable.. its not. Once java ids ported, you tend to get the java platform which is a huge win, but java itself.. not so much. Most JVMs are written in C, so by definition C is available in more locations than java.)
...isn't java on practically all mobile phones released in the past 2 or 3 years?
 
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.. and also C, you see my point :)

Also, java with j2ee, j2se, midp, j2me .. itd a mess. The phones provide various support.. some don't even run the GC!

*Bleh*

jeff
 
Zarneth said:
Linux already has many different content delivery systems, Some distributions (Debian/Ubuntu) manage EVERY single piece of software and library and updates via a package manager which connects to an extensive online repository. [...]

Did I hear the Pandora would be Debian(ARM) based? If so they'll likely use the existing package/content systems which work exceptionally well. In my opinion that's by far the best thing about Debian and it's derivatives.
As I long time linux user I really like the benefits of the apt-get system and central repositorys.

However OpenCDS follows a completely different idea, and is especially for games much more suited.
The main point about the distribution repositorys is that of a stable officially & centrally administrated repository. Sure you can add external rescources, but not very user friendly and always with the danger of messing up your main system. And official updates are always slow and conservative.

OpenCDS on the other hand is almost completely decentralized (downloads could even be done via bittorrent of a similar P2P system), operated only in user-space and can be used for a release quick and often policy with minimal hassle for the users.
In addition it itegrates neatly with the browser, thus the addition of new sources is as easy as it gets and it could even be used to advertise (in the sense of news, not comercials) new projects.

(however I must add this is the idea AFAIK, which is not fully realized jet).
 
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Then again, you lose a central database, and you lose rock-solid stability provided by serious testing.

I like the BitTorrent idea, but I'd also like my Pandora to run without segfaulting all the time. :)
 
I am not proposing that the linux on the pandora should be updated that way :p
Really no problem to let apt-get still handle that.

And the games you install will not checked for rock stability by anyone else than you anyways.
 
Julius said:
As I long time linux user I really like the benefits of the apt-get system and central repositorys.

However OpenCDS follows a completely different idea, and is especially for games much more suited.
The main point about the distribution repositorys is that of a stable officially & centrally administrated repository. Sure you can add external rescources, but not very user friendly and always with the danger of messing up your main system. And official updates are always slow and conservative.

OpenCDS on the other hand is almost completely decentralized (downloads could even be done via bittorrent of a similar P2P system), operated only in user-space and can be used for a release quick and often policy with minimal hassle for the users.
In addition it itegrates neatly with the browser, thus the addition of new sources is as easy as it gets and it could even be used to advertise (in the sense of news, not comercials) new projects.
Good point actually. Another thing to consider is there's limited internal memory (256mb) too. While it may theoretically be possible to design Debian/apt-get packages to install some things to the memory card that would only be the start of the headache.

Apt-get or similar should definitely be used for the base system and common libraries. Everything else could be stand alone packages with a custom extension such as .ppk (pandora package?), which are really just zips or tarballs and will open with an installer ask where on the SD card to install, and will never touch the base system EXCEPT, and this is the magical part, for feeding the dependencies to apt-get. :)

Such a program to handle these packages would be very trivial to write. Keeping it simple is a good way to go. Then the rest would rely on the website to serve the files. Like the GP2X one. (though in my IMHO it could do with an interface tweak or 3, search never works too well and there's that blank agreement you sometimes need to hit i accept for)
 
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Opening up this java thread again, I'm thinking that porting something like Processing might be good for the system, as it would add another environment to program in that is particularly suited to creating more visual apps.

Now as I understand it, Processing is basically a load of libraries that sit on top of Java. I'm wondering how much effort it would be to get it working with Pandora/GP2X.

Processing has lots of libraries for interfacing with sound/network, OpenGL, whatever. If it can be ported over, it'd be great.

I'm not really asking anyone to port it, more asking for opinions of the difficulty.

Processing Website
 
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