A blast from the past: Convert J2ME/MIDP mobile applications to Windows executables

Back in 2004, before smartphones dominated the world, Java 2 Micro Edition (J2ME) was the standard for mobile applications. Nokia, Sony Ericsson, and Motorola phones ran games and apps packaged as JAR files. But there was always one question: "Can we run these on PC?"

That's why Midp2Exe and MidpX were created.

Midp2Exe converts J2ME/MIDP applications (JAR/JAD files) into standalone Windows executables. Simply put, it brings mobile games from your Nokia phone to your desktop.

MidpX takes it further—it's a complete J2ME software management platform integrated into Internet Explorer and Windows Explorer, featuring OTA (Over The Air) provisioning support.

This project is now open-sourced as a piece of software archaeology, preserving a fascinating era of mobile development history.

Here are some classic J2ME games running on Windows via Midp2Exe:

📥 All files are available in the Releases section

You'll need:

• ✅ Midp2Exe120.zip - The converter
• ✅ MidpRuntimeDLL130.zip - Runtime libraries

Extract MidpRuntimeDLL130.zip and choose one of these options:

Option A: Local Installation (Recommended)

• Place the DLL files in the same directory as your converted EXE files

Option B: System-wide Installation

• Copy DLL files to C:\Windows\SysWOW64\ (for x64, requires administrator privileges)
• Copy DLL files to C:\Windows\System32\ (for x86, requires administrator privileges)

Extract Midp2Exe120.zip and use the command line:

# Basic conversion
Midp2Exe -jar yourgame.jar -out yourgame.exe

# With JAD file (recommended)
Midp2Exe -jar yourgame.jar -jad yourgame.jad -out yourgame.exe

Simply double-click the generated .exe file!

Midp2Exe [options]

Options:
  -jar <file>      Input JAR file (required)
  -jad <file>      Input JAD file (optional but recommended)
  -out/-o <file>   Output EXE filename
  -run/-r          Run the application after conversion
  -machine/-m      Target machine format (currently only X86)
  -help/-h         Show help message

Examples:
  Midp2Exe -jar demo.jar -out demo.exe
  Midp2Exe -jar game.jar -jad game.jad -o game.exe -run

• JAR (Java Archive): Contains the actual application code and resources
• JAD (Java Application Descriptor): Contains metadata about the application (name, version, permissions, etc.)

💡 Tip: If you only have a JAR file, the converter will attempt to extract information from the JAR's manifest. However, having both JAR and JAD files ensures the best compatibility.

• OS: Windows XP / Vista / 7 / 8 / 10 / 11
• Architecture: x86 (32-bit)
  • 64-bit Windows users: The converted apps run in 32-bit compatibility mode
• Dependencies: Runtime DLLs (included in MidpRuntimeDLL120.zip)

⚠️ Not Recommended for Modern Systems

MidpX is a Browser Helper Object (BHO) that integrates with Internet Explorer for OTA provisioning. Unless you're specifically using IE for nostalgic purposes, we don't recommend installing MidpX on modern systems.

• Added a toolbar to Internet Explorer and Windows Explorer
• Enabled one-click download and execution of J2ME apps from websites
• Implemented OTA provisioning (the standard mobile app installation method in 2004)
• Integrated with Sun Microsystems Wireless Toolkits (WTK)

• Internet Explorer is deprecated
• Modern browsers don't support BHO plugins
• Security concerns with executing downloaded code automatically

✅ MIDP Support

• MIDP 1.0 full support
• MIDP 2.0 full support
• Nokia UI API emulation

✅ Multimedia

• MIDI music playback (JSR135)
• TONE sound synthesis
• Adjustable volume control
• JPEG and GIF image support

✅ Graphics

• Full Canvas rendering
• Sprite animation
• Double buffering support

⚠️ Current Issues:

• Semi-transparent PNG images not fully supported
• Smart Message templates not implemented
• Some Nokia-specific APIs may not work perfectly
• Maximum 16 simultaneous MIDI channels

These limitations reflect the state of development in 2004 and the challenges of emulating proprietary mobile APIs.

Midp2Exe works by:

1. Porting Sun's KVM (K Virtual Machine) to Windows
2. Implementing NHAL (Native Hardware Abstraction Layer) to bridge Java APIs with Windows APIs
3. Emulating MIDP APIs including display, input, storage (RMS), and networking
4. Multimedia integration through Windows GDI, DirectSound, and MIDI APIs

For developers interested in the technical details, this project demonstrates:

• JVM porting techniques
• API emulation and abstraction layers
• Cross-platform multimedia handling
• Resource-constrained environment optimization

This is primarily an archival project, but contributions are welcome for:

• Documentation improvements
• Bug reports for specific games/applications
• Testing on different Windows versions
• Historical context and stories from the J2ME era

This software is released as Freeware for educational and preservation purposes.

• ✅ Free to use and distribute
• ✅ No warranty provided
• ✅ Use at your own risk

Technology Landscape:

• iPhone just launched (June 2007)
• Android wasn't released yet (2008)
• Nokia dominated the mobile market
• J2ME was the primary mobile development platform
• Feature phones were the norm, not smartphones

Why This Matters:

• Documents an important era in mobile development
• Preserves techniques for VM porting and API emulation
• Enables running classic mobile games that would otherwise be lost
• Educational value for understanding platform evolution

• Medium Article (Traditional Chinese)
• Medium Article (English)
• Sun J2ME Documentation (Archive)

Have questions? Found a bug? Want to share your J2ME memories?

• Open an Issue
• Share your experiences in Discussions
• Found a game that works perfectly? Let us know!

For questions about the original development or historical context, feel free to reach out through GitHub issues.