GP2X Java On Gp2x?

[Parkydr]

Isn't there a program that fully compiles java for arm platforms?

Yes - the GNU toolchain has a Java compiler. However, by doing that, you produce an executable that's platform-specific. The idea of Java is that it's more than just a language: it's a platform, i.e. write once, run anywhere. So when you compile your java app into a jar, that can be executed by any JVM on any platform (at least, that's the theory).

Apropos the performance of Java, it's quite comparable to that of any compiled programs. In fact, the vtable management in Java is generally more efficient than C++. Old version of Java weren't particularly fast, but since 1.2, it's been pretty darn quick indeed. The only inefficiency is the heap usage, but you can optimize that using the commandline settings for your VM.

My experience is "write once, debug every where" especially with GUIs - you can never be sure how they will be set out. I've got Java 1.4 on my old Sun SparcStation 5 and I have never found an app that performs as fast as equivalent C/C++ applications. I can't believe it will be much different on the GP2X.

Related quote

 

[hitbyambulance]

how about J2ME? i looked at the GP2X Wiki and it said that "WinterN" was working on it - the current status was listed as"KVM & CLDC1.1 ported, but problems with double type yet". this is of interest to me, as i work for a mobile game developer, and it would be cool to get prototypes working on the GP2X. i emailed him to get an idea of the app's current state.

 

[PSyMastR]

We will have many problems with double and float on java, as the processor has no FPU.

 

[yaustar]

We will have many problems with double and float on java, as the processor has no FPU.

So we just use fixed point maths instead.

 

[hitbyambulance]

got an answer back from Javier re: J2ME port. he said he was frustrated because he can't make public any binaries or changes in source files - Sun requests that one's port to pass 'many compatibility tests, and the cost of these tests are above $3000'. so the project is officially stalled.

 

[PSyMastR]

Just wait until Java is open source, in about a couple of months, then it will be perfectly fine.

 

[loki666]

java specs are allready open...
and many open implementation allready exist (ie: blackdown jvm)
only sun java implementation will be open source, but we dont need to wait for this.
someone should be able to cross compile blackdown for the gp2x, but dont except graphics without X11

 

[PSyMastR]

java specs are allready open...
and many open implementation allready exist (ie: blackdown jvm)
only sun java implementation will be open source, but we dont need to wait for this.
someone should be able to cross compile blackdown for the gp2x, but dont except graphics without X11

What i meant was that once they go fully open, where anyone can edit and fork, those $3000 fees can be avoided.

 

[loki666]

java specs are allready open...
and many open implementation allready exist (ie: blackdown jvm)
only sun java implementation will be open source, but we dont need to wait for this.
someone should be able to cross compile blackdown for the gp2x, but dont except graphics without X11

What i meant was that once they go fully open, where anyone can edit and fork, those $3000 fees can be avoided.

well i might be wrong, but those $3000 fees can allready be avoided too.
you only need to pass thoses tests to get a certification that your JVM is "standard" compilant.

 

[___]

just a dumb question: Some people wanted mobile phone games running on the gp2x. Now there is a lot of talk about how slow a java implementation on the gp2x would be. I cannot imagine mobile phones to have more memory and faster cpus then our little friend and also do usual mobiles with java support have an FPU??? If java could be implemented, wouldn't it still possible to run mobile phone games? Of course that would still leave speed issues for more advanced projects...

 

[ssj195]

just a dumb question: Some people wanted mobile phone games running on the gp2x. Now there is a lot of talk about how slow a java implementation on the gp2x would be. I cannot imagine mobile phones to have more memory and faster cpus then our little friend and also do usual mobiles with java support have an FPU??? If java could be implemented, wouldn't it still possible to run mobile phone games? Of course that would still leave speed issues for more advanced projects...

I work for a mobile phone games company, and none of our games or that of our sister companies have ever used floating point maths, to my knowledge (we always use fixed-point).

One of my co-workers (who may or may not post on these forums; I have my suspicions ) did some work with J2ME and the PSP, but I can't quite remember what he accomplished - I think he ported a java run-time to it. It ran the few sample games he showed perfectly.

Actually, now that I come to think of it, those games might have had to be re-compiled with minor modifications in order to run, but I can't quite recall :/

 

[sephiroth111]

just a dumb question: Some people wanted mobile phone games running on the gp2x. Now there is a lot of talk about how slow a java implementation on the gp2x would be. I cannot imagine mobile phones to have more memory and faster cpus then our little friend and also do usual mobiles with java support have an FPU??? If java could be implemented, wouldn't it still possible to run mobile phone games? Of course that would still leave speed issues for more advanced projects...

I work for a mobile phone games company, and none of our games or that of our sister companies have ever used floating point maths, to my knowledge (we always use fixed-point).

One of my co-workers (who may or may not post on these forums; I have my suspicions ) did some work with J2ME and the PSP, but I can't quite remember what he accomplished - I think he ported a java run-time to it. It ran the few sample games he showed perfectly.

Actually, now that I come to think of it, those games might have had to be re-compiled with minor modifications in order to run, but I can't quite recall :/

Looking at it, the chipsets for the phones probably aren't even above 66mhz. Thinking about it, the phone is probably one of the worst things for games, (the ngage aside, but then again...).

 

[PSyMastR]

Hey, I love my N-Gage lol.

Anyway, I have looked into the ARM compilers for Java, and it seems pretty simple. Since, Im pretty experienced with java, Ill take a look around and see what I can come up with.

 

[bpmurray]

well i might be wrong, but those $3000 fees can allready be avoided too.
you only need to pass thoses tests to get a certification that your JVM is "standard" compilant.

I think you're right about that. AFAIK, you have to pass the TCK before you can claim that it's Java (or J2ME, in this case). If you claim it's "K#" (somebody else has apparently taken the name "J#") it should be OK.

 

[noreason]

Looking at it, the chipsets for the phones probably aren't even above 66mhz. Thinking about it, the phone is probably one of the worst things for games, (the ngage aside, but then again...).

i transferred yesterday Sonic1 to my SonyEricsson V600i and wow it seems like it's the whole game fullspeeld ok i agree the gp2x has bigger screen and way better buttons but hey that games on mobile phone's are getting better every day (fifa world cup 3d wtf)