i am sure there is one out there… it will be silly to write my own.  okie. keep googling.

(the next morning)
feeling very stupid.. of course it is covered in jdk..  it is InetAddress.  dns lookup caching behaviour is defined in here too…

byte vs unsign byte

(after a couple days)
No!  InetAddress is not what I want… ok writing our own validation logic for now…