Hi @pthalin , and everyone else :)

Testing game-compatibility with BittBoyJ2ME has been a wonderful, yet horrific, trip down memory lane. Here is a quick rundown of my experience as a concatenated bug report/general advice:

1. Neither the numpad diagonals (obviously) nor the joystick action key (joystick center button) is available, so games requiring either of these will not be playable. Is the latter possible to implement? One of the shoulder buttons of the PocketGo maybe?

2. The emulator seemingly does not loop music (neither at the menu nor in-game), so once the music has finished playing one time the game will be dead silent. Is this fixable?

3. Games with 176 pixel width (176x220, 176x208, 176x204) render within the confines of the draw box. I love 176x220 games (in fact one of my images ranked number 1 for 10 years on Google Images for the search term '176x220'), but why are we not utilizing the entire screen real estate of the PocketGo (320x240)? This would require the screen rendering to be rotated to accomodate for 240x320 games though.

4. Games with <220 height will show a small white rectangle (or rendering artefacts) at the bottom center. I assume this rectangle is part of how the emulator draws to screen. Is it possible to move the rectangle to the top of the screen, as the rectangle then would always be completely hidden by the overlaying game?

5. Only bitmap ('2D') games are supported. M3G APIs have not been integrated, so no polygonal ('3D') games will run.

6. Spaces in game file names are not supported, and will prevent the emulator from loading.

7. The emulator has average-to-low game compatibility, much thanks to J2ME being such fractionated platform in the first place. Expect the majority of games to either have graphical glitches, sound/music not playing, not registering key input, freezing at load, or simply refusing to load at all. However, with enough patience, you'll end up with quite a respectable collection of compatible mobile games.

Keeping in mind that I'm quite picky when it comes to games, I'm attaching an image of the box art of my personal final 20 mobile games for reference.

Keep up the good work!

Sincerely,
BryMD

Bittboy J2ME

Usage & Device installation 🎮

Description:

This is an emulator (runtime environment, in fact) for Java 2 ME software (J2ME). It is compatible with Bittboy (and PocketGo).

Keys mapping: ⌨️

• A = (5) FIRE
• B = (3)
• TA = (7)
• TB = (1)
• R = Force Exit
• SELECT = SOFTKEY LEFT
• START = SOFTKEY RIGHT

Notes: 📝

• Resolution of games must be 176x220.
• Sound support if CFW 1.3.3 or later.
• You may have to try several versions of a game to find a compatible version.

Installation: 📥

1. Copy the folder bittboy-j2me/ to emus/
2. Copy the file menu/bittboy-j2me to gmenu2x/sections/emulators/
3. Create the folder main/roms/j2me (put jar files here)

Building project 🛠️

Required tools

• Bittboy buildroot uClibc
• Java SE Development Kit 6u45

Source code

Cloning the repo

cd <my-dev-folder>
git clone https://github.com/pthalin/bittboy-j2me.git

Setup Bittboy buildroot uClibc

cd /opt
sudo mkdir buildroot-bittboy
sudo chown <USERNAME HERE> buildroot-bittboy
git clone https://github.com/bittboy/buildroot.git ./buildroot-bittboy
cp <my-dev-folder>/bittboy-j2me/buildroot_cfg/config buildroot-bittboy/.config 
cd buildroot-bittboy
make sdk

Note: You may have to install missing packages if it fails.
(The last step will take quite some time... go take a cup of tea)

Ubuntu JDK installation 💻

Download jdk-6u45-linux-i586.bin file from oracle.com

Make the downloaded bin file executable:
chmod +x jdk-6u45-linux-i586.bin

Extract the bin file;
./jdk-6u45-linux-i586.bin

Create a folder called "jvm" inside /usr/lib if it does not already exist:
sudo mkdir /usr/lib/jvm

Rename and move the extracted folder to the jvm folder:
sudo mv jdk1.6.0_45 jdk1.6.0_45_x86
sudo mv jdk1.6.0_45_x86 /usr/lib/jvm/

To install the Java source run the following commands:
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_45_x86/bin/java 1
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_45_x86/bin/javac 1
sudo update-alternatives --install /usr/bin/javah javah /usr/lib/jvm/jdk1.6.0_45_x86/bin/javah 1
sudo update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.6.0_45_x86/bin/javaws 1
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.6.0_45_x86/bin/jar 1

To make this default java:
 
sudo update-alternatives --config java
sudo update-alternatives --config javac
sudo update-alternatives --config javah
sudo update-alternatives --config javaws
sudo update-alternatives --config jar

To verify Java has installed correctly run this command.
java -version

Compiling

cd <my-dev-folder>/bittboy-j2me/phoneme_advanced_mr2/cdc/build/linux-arm-generic
make
cd <my-dev-folder>/bittboy-j2me/midpath
./build.sh
cd <my-dev-folder>/bittboy-j2me/
./release.sh

This is the output:

<my-dev-folder>/bittboy-j2me/release/bitboy-j2me.zip

Authors

Porting to Bittboy: pthalin (github.com/pthalin)
Icon by: MediaDesign (https://www.deviantart.com/mediadesign)

I used a translation site because my English is not good.
The java emulator came up and made me dig out miyoo to play with it again.After trying out many games, I found that some of the text within the game would not be displayed. Because there is no way to find java games in English, and I think you should have tested it, so I guess it is possible that the Chinese language library is missing. Of course, after all, I don't know much about this and can only guess. If you can, I hope you can solve this problem.It has been a long time wish to have a small device with buttons to play the previous java games.
I would like to thank you very much for your hard work and dedication so that this little machine can be rejuvenated.

this would help only if bittboy has emulator
so could you port bittboy-j2me to any platform that retroarch or bizhawk support

Totally LOVE your project! Whipped up a quick FontiGrid compliant icon for myself. Grab it for yourself if you're interested.

On a side note, do you know if bittboy-j2me prefers any particular flavor of .jars (ie. Nokia, Sony Ericsson, Samsung, Siemens etc.)?

Keep up the good work!

When the emulator locks up, you could press the select and start button. To close the emulator and return to the game list!
Same in simplemenu when you press select and start it turns off the laptop.

Hello, i have a question, How i can setup J2me to work in simple menu. i use Powkiddy V90 and i already create selection of j2me but the problem is i don't know where the execs of J2me to set to work. can anyone help me find execs of j2me ?
My code in selecion is :
[J2ME]
execs = ?
romDirs = /mnt/roms/J2ME/
romExts = .jar,.jad
but i can't find execs file to work