CoreJ2

Run classic Java ME (J2ME) games natively on iPhone & iPad.

Embedded OpenJDK Mobile · FreeJ2ME · SwiftUI · Open Source

Miami Nights: Singles in the City — gameplay on a physical iPhone

Documentation · Compatibility · Architecture · Roadmap · Source

---

Current Status

Feature	Status
Embedded OpenJDK Mobile	✅
FreeJ2ME Runtime	✅
Commercial MIDlets	✅
LCD Rendering	✅
Touch Input	✅
Virtual Keypad	✅
Save / Load (RMS)	✅
Multiple Launch Cycles	✅
Gameplay	✅
Silent Audio Compatibility	✅
Native Audio Playback	🚧 In Progress
Compatibility Expansion	🚧 In Progress

---

Reference Game

Miami Nights: Singles in the City

Validated on:

• Physical iPhone
• Embedded OpenJDK Mobile
• FreeJ2ME
• SwiftUI frontend

Current validation

Check	Result
Launch	✓
Menus	✓
Gameplay	✓
Save	✓
Load	✓
Dialogs	✓
Stable gameplay	✓
No crashes during manual play session	✓

Remaining work

• Native MMAPI audio backend
• Compatibility expansion

 

Gameplay and menu — Miami Nights on device

---

Showcase

Preview	Caption
	Miami Nights — commercial title, playable session on physical iPhone
	Tetris — LCD rendering and virtual keypad
	Astroids — touch + keypad input path

Screenshot	Caption
	Library — SwiftUI game list and import
	Tetris — FreeJ2ME LCD surface
	Astroids — device capture
	Gryzzles — RMS / save path validation

More captures: Screenshots

---

Gameplay Videos

Full device recordings (MP4):

Title	Video
Miami Nights	miami-nights.MP4
Tetris	tetris.mp4
Astroids	astroids.MP4

HTML5 playback is available on the documentation site.

---

Architecture

SwiftUI
  ↓
Bridge
  ↓
Runtime Host
  ↓
Embedded OpenJDK Mobile
  ↓
FreeJ2ME
  ↓
Commercial MIDlet

Details: Architecture

---

Roadmap

Completed Milestones

• Embedded JVM (OpenJDK Mobile Zero)
• FreeJ2ME Integration
• AWT
• ImageIO
• JPEG
• FontManager
• RMS
• Commercial MIDlets
• Miami Nights gameplay

Current Work

• Native MMAPI Audio
• Compatibility Database

Future Work

• Controller support
• Per-game settings
• Save States
• Performance optimization
• Shader pipeline

Full plan: Roadmap

---

Documentation

Guide	Description
Getting Started	Install and launch a MIDlet
Why CoreJ2?	Vision and technical rationale
Architecture	Layer ownership
Compatibility	Device-validated matrix
Roadmap	Milestones and next steps
FAQ	Common questions

python3 -m venv .venv-docs && source .venv-docs/bin/activate
pip install -r requirements-docs.txt
mkdocs serve

---

Brand

Official assets: assets/branding/ · Guidelines

Palette: #2563EB · #60A5FA · #0B1220 · #FFFFFF · #94A3B8

---

Status

🚧 Alpha · v0.9.0-alpha — commercial J2ME titles run on physical iPhone with embedded OpenJDK Mobile. Native audio playback and broader compatibility are in progress.

---

Contributing

See CONTRIBUTING.md, CODE_OF_CONDUCT.md, and SECURITY.md.

---

License

Application licensing: see repository terms when published.
Vendor FreeJ2ME: GPL-3.0 (Vendor/FreeJ2ME).
Brand assets: original CoreJ2 identity (see branding guidelines).

---

GitHub · Documentation · Roadmap · Compatibility

Copyright © CoreJ2 contributors