It's an implementation of Java ME in JavaScript for Firefox OS.
Available at Firefox OS Marketplace
Hard to say. There's a lot of different classes in J2ME ecosystem, not only MIDP. Currently it supports most of Java bytecode, part of MIDP and it's able to run few J2ME games and application.
Performance is great. It's intended to run smoothly on Firefox OS crapphones like Keon so must work as fast as possible. Thanks to aggressive JIT optimizations it's much faster than any other JVM written in JavaScript.
It exists. You only have to clone this repository and push to your phone. If you don't want any superfluous files you can use $ ./buildApp.sh
.
Feel free to submit a pull requests. There's also short guide how to write your own pseudo-Java classes.
Normal edition is privileged Firefox OS app with more working features, but it's slower. X edition is faster, but has less features. It's good enough for gaming.
Milestone 0.1 - Hello world (test.jar) works (done)
Milestone 0.2 - Picross (picross.jar) works (done)
Milestone 0.2.5 - Play around... (done)
Milestone 0.3 - Run FPC benchmark (done)
Milestone 0.4 - Optimizations (done)
Milestone 0.5 - Firefox OS application (rejected)
Milestone 0.6 (done)
Milestone 0.7
Milestone 0.8
Milestone 1.0
Milestone 1.1
Somewhere in future...