¶ FreeJ2ME Add-On Guide
FreeJ2ME is an open-source Java ME emulator that allows users to play classic mobile Java games (J2ME) on modern devices. It supports a wide range of JAR files and offers two emulation methods: the standard emulator and RetroArch's libretro core. Both provide customizable controls and graphics options.
This package includes all necessary resources for full compatibility with Batocera out of the box.
¶ 📥 Installation
FreeJ2ME can be installed via Batocera Unofficial Add-Ons (BUA) or directly through a terminal script.
¶ 🧩 Method 1: BUA (Recommended)
- Open Batocera Unofficial Add-Ons from the Ports menu.
- Locate and install FreeJ2ME.
- Once installed, FreeJ2ME will appear in your game list under Java.
¶ 🖥️ Method 2: Terminal Installer
Alternatively, run the following in a terminal:
curl -L bit.ly/drl-j2me | bash
This will install both:
- Standard FreeJ2ME Emulator
- FreeJ2ME (RetroArch core)
¶ 🔄 Switching Between Emulators
After installation, a special launcher called -Update_j2me will appear in the Ports menu.
- Launch this to toggle between:
- Standard emulator (recommended for most games)
- Libretro-based emulator (via RetroArch) — experimental, still in testing phase
This feature ensures a flexible and smooth experience across different game types.
¶ 🎮 How to Play
FreeJ2ME supports a wide variety of Java ME games from old Nokia, Sony Ericsson, and Motorola phones.
Java games will automatically appear in the Java menu when placed in:
/userdata/roms/j2me
¶ Steps:
- Copy
.jarfiles to/userdata/roms/j2me - Update the game list from the Batocera menu.
- Go to the Java section and launch a game.
- Use the Options Menu to configure controls and settings.
¶ ⚙️ Configuration
- Input: Gamepad, keyboard, or touchscreen.
- Graphics: Adjust resolution, aspect ratio, and scaling.
- Performance: Enable JIT for smoother gameplay.
- Saves: Save/load states in supported games.
Most common gamepads are auto-detected; you can remap buttons in the emulator options if needed.
¶ 🎮 Controller Mappings
¶ 📍 Common Controls (Standard Emulator)
| Gamepad Input | Key | Emulates |
|---|---|---|
| Start | Esc | FreeJ2ME Options |
| 🔺/X or L1 | Q | Options/Select |
| ⭕/A or R1 | W | Back |
| L2 | E | * |
| R2 | R | # |
| D-PAD or L-Analog | 1–9 | Number Pad |
| □ / Y | A | (Configurable / unused) |
| ✖️ / B | Enter | OK / Action Key |
¶ 🎮 Directional Shortcuts (Analog / Arrow Keys)
| Input | Key | Emulates |
|---|---|---|
| D-PAD UP / L-Analog UP | Up Arrow | 2 |
| D-PAD DOWN / L-Analog DOWN | Down Arrow | 8 |
| D-PAD LEFT / L-Analog LEFT | Left Arrow | 4 |
| D-PAD RIGHT / L-Analog RIGHT | Right Arrow | 6 |
| R-Analog LEFT | Diagonal Top-Left | 1 |
| R-Analog UP | Diagonal Bottom-Left | 3 |
| R-Analog DOWN | Diagonal Bottom-Right | 7 |
| R-Analog RIGHT | Diagonal Top-Right | 9 |
¶ 🧭 Nokia-Style Keypad Mapping
| Input | Key | Emulates |
|---|---|---|
| D-PAD UP / L-Analog UP | Up Arrow | Navigate Up |
| D-PAD DOWN / L-Analog DOWN | Down Arrow | Navigate Down |
| D-PAD LEFT / L-Analog LEFT | Left Arrow | Navigate Left |
| D-PAD RIGHT / L-Analog RIGHT | Right Arrow | Navigate Right |
| □ / Y | A | (Configurable / unused) |
| ✖️ / B | Enter | Action Key (OK button) |
¶ 🛠️ Troubleshooting
| Issue | Solution |
|---|---|
| Game won't launch | Ensure .jar file is valid and in the correct folder. |
| Controls unresponsive | Use the emulator's input menu to remap. |
| Laggy performance | Enable JIT and lower resolution settings. |
| No sound | Try enabling compatibility mode in audio settings. |
¶ 📝 Extra Tips
- Both emulator versions support separate config profiles.
- For classic Nokia-style layouts, use the provided D-Pad + analog stick combos.
- Save/load features may behave differently between emulators – test compatibility per game.
- Some games may work better in the standard emulator than in the RetroArch version.
Enjoy your favorite Java ME classics on Batocera! 😄
Need help or want to contribute? Visit the GitHub project page for updates and support.