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https://github.com/hex007/freej2me

A free J2ME emulator with libretro, awt and sdl2 frontends.
https://github.com/hex007/freej2me

awt emulator emulator-frontend j2me libretro sdl2 sdl2-frontends

Last synced: 3 months ago
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A free J2ME emulator with libretro, awt and sdl2 frontends.

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README 

        
# freej2me



![Java CI](https://github.com/hex007/freej2me/workflows/Java%20CI/badge.svg)



A free J2ME emulator with libretro, awt and sdl2 frontends.



Authors :

- David Richardson [Recompile@retropie]

- Saket Dandawate  [Hex@retropie]



---



## Controls



* `Q` and `W` for left and right softkeys.

* Arrow keys for nav, unless phone is set to "Standard", when arrow keys become 2, 4, 6, and 8.

* Numbers work as expected, the number pad is inverted (123 swap with 789, like a phone)

* `E` and `R` are alternatives to `*` and `#`.

* Enter functions as the Fire key or `5` on "Standard" mode

* ESC brings up the settings menu

* In the AWT frontend (freej2me.jar) `Ctrl+C` takes a screenshot and `+`/`-` can be used to control the window scaling factor



Click [here](KEYMAP.md) for information about more keybindings



## Links

Screenshots:

  https://imgur.com/a/2vAeC



Discussion/Support thread:

  https://retropie.org.uk/forum/topic/13084/freej2me-support-thread



Development thread:

  https://retropie.org.uk/forum/topic/11441/would-you-like-to-play-nokia-j2me-games-on-retropie/



----

**FreeJ2ME Jar Compilation:**



>From the root directory, running the following commands:

>```

> > cd freej2me/

> > ant

>```

> Will create three different jar files inside `build/`:

>

> `freej2me.jar` -> Standalone AWT jar executable

> 

> `freej2me-lr.jar` -> Libretro executable (has to be placed on the frontend's `system/` folder, since it acts as a BIOS for the libretro core and runs J2ME jars)

>

>`freej2me-sdl.jar` -> Jar executable meant to be used in conjunction with SDL2

>

>Both the Libretro and SDL2 jar files need additional binaries to be compiled before use. Look at the additional steps below if you're going to use one of them.



**Building the SDL2 binary:**

>

>To build the SDL2 binary, run the following commands from the root directory:

> ```

> # SDL2 binary compilation

> > cd src/sdl2

> > make

> > make install

> ```

>

> SDL2 allows FreeJ2ME to run on a Raspberry Pi.



**Building the Libretro core**



> **For linux:**

>To build the libretro core, open a terminal in freej2me's folder run the following commands from there:

>```

># libretro core compilation

> > cd src/libretro

> > make

>```

>This will build `freej2me_libretro.so` on `src/libretro/`, which is the core libretro will use to interface with `freej2me-lr.jar`.

>

>Move it to your libretro frontend's `cores/` folder, with freej2me-lr.jar on `system/` and the frontend should be able to load j2me files afterwards.

>

>NOTE: The core DOES NOT WORK on containerized/sandboxed environments unless it can call a java runtime that also resides in the same sandbox or container, keep that in mind if you're running a libretro frontend through something like flatpak or snap for example.

>



> **For windows:**

>To build the libretro core for windows, first you'll need mingw, or MSYS2 64. **`This guide uses MSYS2`** as it's easier to set up and works closer to linux syntax.

>

> Download MSYS2-x86_64 and install it on your computer. By default it will create a linux-like 'home' folder on C:\msys64\home\ and will put a folder with your username in there. This is where you have to move the freej2me folder to, so: `C:\msys64\home\USERNAME\freej2mefolder` for example.

>

> With the folder placed in there you can build the core, open the MSYS2 UCRT64 terminal from your pc's start menu, and run the following commands:

>```

> # Installing 'mingw-w64' and 'make' on msys2

> > pacman -S mingw-w64-ucrt-x86_64-gcc

> > pacman -S make

>

> # libretro core compilation

> > cd freej2mefolder/src/libretro

> > make

>```

>This will build `freej2me_libretro.dll` on `freej2mefolder/src/libretro/`, which is the core libretro will use to interface with `freej2me-lr.jar`.

>

>Move it to your libretro frontend's `cores/` folder, with freej2me-lr.jar on `system/` and the frontend should be able to load j2me files afterwards.

>

>NOTE: The windows core has only been tested on Windows 10 x64.



----

**Usage (applies to AWT and SDL):**



Launching the AWT frontend (freej2me.jar) will bring up a filepicker to select the MIDlet to run.



Alternatively it can be launched from the command line: `java -jar freej2me.jar 'file:///path/to/midlet.jar' [width] [height] [scale]`

Where _width_, _height_ (dimensions of the simulated screen) and _scale_ (initial scale factor of the window) are optional arguments.



The SDL2 frontend (freej2me-sdl.jar) accepts the same command-line arguments format, aside from the _scale_ option which is unavailable.



When running under Microsoft Windows please do note paths require an additional `/` prefixed. For example, `C:\path\to\midlet.jar` should be passed as `file:///C:\path\to\midlet.jar`



FreeJ2ME keeps savedata and config at the working directory it is run from. Currently any resolution specified at the config file takes precedence over the values passed via command-line.



---

**How to contribute as a developer:**

  1) Open an Issue

  2) Try solving that issue

  3) Post on the Issue if you have a possible solution

  4) Submit a PR implementing the solution



**If you are not a developer:**

  1) Post on discussion thread only



**Roadmap:**

  - Get as many games as possible to work well.

  - Document games that work well in the wiki

  - Reduce as many bugs as possible