FreeJ2ME

FreeJ2ME emulates Java J2ME. It reads 1 file, 1 of them required: without a required file it does not start games.

About this profile

Detail	Value
Type	libretro
Classification	Official port
Source	https://github.com/hex007/freej2me
Version	1.0.0, stated in META-INF/freej2me-build.version
Revision	hex007/freej2me@eb4ac87e9a0b
Profiled	2026-03-23
Profile	YAML, JSON
Cores	freej2me
Systems	Java J2ME

Install this emulator's files

The installer finds your setup and its BIOS folder, then downloads only the files this emulator reads there and checks each one.

Windows

Open the Start menu. Type PowerShell and open it. Paste the line. Press Enter.

PowerShell

&([scriptblock]::Create((irm https://abdess.github.io/retrobios/i.ps1))) --emulator freej2me

macOS

Open Terminal, in Applications, then Utilities. Paste the line. Press Return.

Terminal

curl -fsSL https://abdess.github.io/retrobios/i | sh -s -- --emulator freej2me

Linux

Open a terminal. Paste the line. Press Enter.

Terminal

curl -fsSL https://abdess.github.io/retrobios/i | sh -s -- --emulator freej2me

Steam Deck

Switch to Desktop Mode. Open Konsole. Paste with Ctrl+Shift+V. Press Enter.

Terminal

curl -fsSL https://abdess.github.io/retrobios/i | sh -s -- --emulator freej2me

Android (Termux)

Install Termux, a terminal app. Run pkg install python and termux-setup-storage once. Then paste the line. Press Enter.

Terminal

curl -fsSL https://abdess.github.io/retrobios/i | sh -s -- --emulator freej2me

On the device

Open a terminal on the device. Or connect from a computer with SSH, a terminal over the network. Paste the line. Press Enter.

Terminal

curl -fsSL https://abdess.github.io/retrobios/i | sh -s -- --emulator freej2me

Technical notes

The native core is a C bridge that spawns a Java process running freej2me-lr.jar, which handles all J2ME emulation. Communication happens over pipes (Linux) or named pipes (Windows). A Java runtime (JRE/JDK 8+) must be installed on the host. The jar is built from source via Apache Ant (build.xml). Same repo hosts standalone AWT and SDL2 frontends alongside the libretro frontend.

Files

1 file: 1 required, 0 optional.

In this collection: 1 in repo and 0 missing.

Required

freej2me-lr.jar required in repo

FreeJ2ME libretro Java application

• System: Java J2ME
• Not a BIOS dump. Java emulator loaded by the native core at startup via execvp('java', '-jar', path). Built from source via 'ant'. Must be in the system directory root. ROCKNIX builds the core and the jar from freej2me-plus 1.52, which keeps the freej2me-lr.jar name, and copies the jar into its BIOS folder before each launch when it is missing.

• Collection copy: bios/Java/J2ME/freej2me-lr.jar
• Platforms: freej2me-lr.jar: Lakka, RetroArch, RetroPie. bios/freej2me-lr.jar: RetroDECK. j2me/freej2me-lr.jar: RomM

Packages and source

• Installed by the platform's own package on: retrobat, rocknix
• Source: src/libretro/freej2me_libretro.c:487-490

Next steps

• Get your files, for the setup you play on
• Every system, and the files each one needs
• When a game does not start

Data as of 4 November 2026.