All of the high end (Nokia S80 style) phones can do flash light but there are still problems with it. J2ME runs across nearly all phones but some of the older phones (Nokia S40 style) have very small screens and the Java runtime seems to be painfully slow (the cpu's are quite beefy buy I suspect the memory access is slooooow). Be aware that despite it being Java there are quirks across the 50+ mobile phones that are in common use around the world. There are a lot of small companies that specialize in testing across this range though.