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 Code

---

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 with embedded OpenJDK Mobile, FreeJ2ME, and a SwiftUI frontend.

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 with virtual keypad

In-game menu on device

---

Showcase

GIF previews

Miami Nights — commercial title, playable session

Tetris — LCD rendering and virtual keypad

Astroids — touch + keypad input path

Screenshots

Library — SwiftUI game list and import

Tetris — FreeJ2ME LCD surface

Astroids — device capture

Gryzzles — RMS / save path validation

See Screenshots.

---

Gameplay Videos

Full device recordings live in the repository (hosted outside the Pages artifact to keep deploys reliable).

Title	Recording
Miami Nights	Download MP4
Tetris	Download MP4
Astroids	Download MP4

GIF previews are above; use the downloads for full-length playback.

---

Architecture

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

Full layer ownership: Architecture

---

Compatibility Database

Device-validated titles live in the public Compatibility matrix. Expansion is ongoing (Epic 12).

Browse compatibility →

---

Documentation

Page	Why
Why CoreJ2?	Vision and technical rationale
Getting Started	First launch
Compatibility	Device-validated matrix
Architecture	Ownership by layer
Roadmap	Completed, current, future
Milestones	Engineering timeline
FAQ	Common questions
Branding	Visual identity

---

🚧 Alpha · v0.9.0-alpha · GitHub · Roadmap · Compatibility