[zigzigzag]

HotSpot at least doesn't have terrible startup time. 50msec for Hello World and about 500msec to get a JavaFX window on the screen with a button in it.

The .NET CLR isn't really "fast without requiring lots of warmup". It's a much simpler design that out of the box simply compiles each method the first time it's used. It doesn't "warm up" because it doesn't do profile guided or speculative optimisations at all. The weakness of the CLR is one reason C# pushes more optimisation complexity onto the developer e.g. having to mark virtual methods explicitly instead of methods being virtual by default. With respect to memory usage I guess it's not much different.

There are JVMs designed for old candybar feature phones (J2ME etc). The issue is not "can you make a mobile JVM" as the answer is clearly yes for any type of phone, even very old ones. The issue is "how much fancy technology can you fit in that space".

[naasking]

> With respect to memory usage I guess it's not much different.

Memory use is quite different due to reified generics and value types.

[PeCaN]

Oh, I'm not saying JVMs can't work on tiny devices (heck, there are JVMs on everything from 2005 feature phones to Intel ME to some random tiny SuperH chip in a car), just that a high-performance JVM has so far not been designed for that particular use case.