Why did this matter for gaming? Because was the killer feature. A developer in Finland could compile a game once, and in theory, it would run on a Nokia in India, a Sony Ericsson in Brazil, or a Motorola Razr in the USA. In practice, "Write Once, Run Anywhere" turned into "Write Once, Debug Everywhere," but it was revolutionary for its time.
(Android) and FreeJ2ME (PC) are the standard emulators. They allow you to load .jar files, map touch controls to virtual keys, and even scale the resolution. Java ME Games
if (accuracy > 80 && difficultyLevel < 5) difficultyLevel++; // harder: faster enemies, less power-ups else if (accuracy < 40 && difficultyLevel > 1) difficultyLevel--; // easier: slower, more forgiving timing Why did this matter for gaming