Homebrew run mobile games .jar on 3ds, is this possible?

[Thee_Stranger]

Any updates on this? lol.
I had two J2ME games that I really liked on my ol' Motorola RAZR phone -- they were all the rage, kids! -- back in '05 - '06ish. War of the Worlds & XIII, by Gameloft. They were both actually pretty damn good for what they were. I would love to replay them on a 3DS, with a proper button layout. If they make that happen, I can pretty much complete my entire portable gaming history via my 3DS. How wonderful that would be. A CFW N3DS is such a beautiful machine.

Some wonderful wizard dev make this happen, please. Thank you.

 

[Dionicio3]

Any updates on this? lol.
I had two J2ME games that I really liked on my ol' Motorola RAZR phone -- they were all the rage, kids! -- back in '05 - '06ish. War of the Worlds & XIII, by Gameloft. They were both actually pretty damn good for what they were. I would love to replay them on a 3DS, with a proper button layout. If they make that happen, I can pretty much complete my entire portable gaming history via my 3DS. How wonderful that would be. A CFW N3DS is such a beautiful machine.

Some wonderful wizard dev make this happen, please. Thank you.

There hasn't, and most likely won't ever be any updates. It really isn't feasible to make a JRE on the 3DS

 

[Thee_Stranger]

There hasn't, and most likely won't ever be any updates. It really isn't feasible to make a JRE on the 3DS

How is it not feasible? From where I'm sitting, they've done much more complex ports and sorcery on the 3DS, with much more demanding software. I don't really understand how things like Super Mario 64, Tomb Raider, Quake, etc. were perfectly feasible, but cheap early 00's mobile games aren't. If we're talking from purely a demand and desire standpoint, sure.

 

[Dionicio3]

How is it not feasible? From where I'm sitting, they've done much more complex ports and sorcery on the DS, with much more demanding software. I don't really understand how things like Super Mario 64, Tomb Raider, Quake, etc. were perfectly feasible, but cheap early 00's mobile games aren't. If we're talking from purely a demand and desire standpoint, sure.

Java and C are completely different. You'd need to make a Java interpreter AND modify the jar to work on the 3DS.

 

[Thee_Stranger]

Java and C are completely different. You'd need to make a Java interpreter AND modify the jar to work on the 3DS.

If you have software that interprets Java, why would you need to additionally modify the rom?

But, whatever. I'm a complete layman when it comes to the technical details. I'll take your word for it that it's a massive undertaking/technical nightmare -- as other users have pointed out -- but do not understand why.

 

[Deleted member 586536]

If you have software that interprets Java, why would you need to additionally modify the rom?

java works across platforms. Sure, it's theoretically possible. However using java doesn't automagically make it work on a different platform. Depending what calls are used, or what features, it may specifically be designed around mac os or windows, or linux. Usually that's not the case, as java itself, targets those platforms usually well enough, but sometimes it happens.
However, since the 3ds is nothing like windows, macos, linux, (x86 platforms) your very much not guaranteed for those jars to just work on a 3ds. It may use x86 calls that arm just has no equivalent for built into the (java) interpreter.

You likely need a series of patches since the jar may ask things that the 3ds os just, doesn't have an equivalent for. and interprets are extremely heavy, something the 3ds already struggles with.


For context, those ports are compiled, there's no interpreter, it's as close to bare metal (without writing assembly or machine code) as you possibly can get, with targeting specific hardware and an existing operating system (3ds home menu and processes)


An interpreter however, takes instructions that only the interpreter can read, and then converts it into code on the fly the system can actually execute.
If I had to make a diagram

for something like written into c and compiled:
cpu(s)--->3ds processes (these handle read writes,and a whole bunch of hardware related stuff for you with dynamic libraries, if I'm not mistaken the 3ds uses them)<--->3ds app (from here it just works with the code instructed. Pieces may be put in and out, but all of it is generally machine code)


for something written with an interpreter
cpu(s)--->3ds processes-->3ds app<-->interpreter<--->jar/py/whatever is fed into the interpreter--->converted (readable to the machine) code.

 

[gnmmarechal]

Java and C are completely different. You'd need to make a Java interpreter AND modify the jar to work on the 3DS.

Actually, you wouldn't really need to modify the jars themselves. I'm sure someone could port PSPKVM over if they really wnted to.
https://github.com/vadosnaprimer/pspkvm


This is a thing as well: https://gbatemp.net/threads/pstros-nds.91859/

 

[Dionicio3]

Actually, you wouldn't really need to modify the jars themselves. I'm sure someone could port PSPKVM over if they really wnted to.
https://github.com/vadosnaprimer/pspkvm


This is a thing as well: https://gbatemp.net/threads/pstros-nds.91859/

Wow, guess I'm wrong, alright

 

[Thee_Stranger]

RetroArch for 3DS includes a core called SquirrelJME, and it can supposedly run J2ME. I haven't tried it myself though.

Nice. Well, I just tried it, and it did not work. Got a peculiar error message that was particularly difficult to read. Near as I can decipher, it said:

"Failed to load ROM! If it is corrupt/missing, visit https://squirreljme.cc/uu/download.(??) and download the ZIP titled SummerCoat ROM"
If anyone has any experience with this particular emulator on 3DS RetroArch and could drop me a line on any info, I'd appreciate it.

I did, however, also install pstros nds.
Ran it on my 3DS via TWiLight Menu, and that did successfully play War of Worlds for me. And it runs perfectly, near as I can tell. XIII, however, suffers from atrociously bad lag. There's spots where it's probably going, like, 5 fps. So, that one was kind of a bust. Still very cool. But it also lacks sound, and options. Fortunately, the only J2ME games I'm familiar with were quite minimal on sound and music, but it'd still be nice to have. Some more options/customization would also be quite nice.

Beggars can't be choosers. I'm certainly happy this exists. But it's a very old emulator for the original DS, produced in 2008, and hasn't been updated at all in the last 14 years. I would imagine such a program tailored for the N3DS would enjoy much better compatibility and capability.

Thanks for the input and info, everybody. ^^

 

[Tetramino]

There is no desire to do this, and there never will be.
You are talking about j2me. An obscure java implementation that never enjoyed much popularity/development.
It would take more work to create a j2me runtime than it would to just remake the small handful of crappy games that were developed for it.

I know I'm like, MULTIPLE years later, but there is def some audience for this.

 

[samaret]

If you'd like to play java games on 3DS and don't mind a bit longer emulation process than usual then I would recommend Pstros NDS, It was made for nintendo DS from what originally was a java emulator for a GBA so you will need to open it with twilight menu. Just run the .nds file with TM and then select the .jad file to emulate. Most games are usually .jar so you'll need a program called jadmaker to create an .jad file from .jar one, both files must go into a 3ds directory.