added apache commons-io as a dependency because writing your own HTTP handlers is bonkers.
static final is a nice optimization trick, but this is an Updater class. If this is causing you performance problems, you're doing everything wrong and making my life testing a pain.
stop with the private constructors. nobody cares.
enough with the static final methods already, they make testing painful.
swapped out custom HTTP code to use Apache Common IO instead
got rid of unnecessary TODO.   Assume the Android Framework can and will do horrible things.
got rid of unnecessary casting
drop dead code
added guava dependency