I have to write a program that mimics a digital clock w/ seconds, minutes, and hours. I'm sure I can get the displays working on my own and everything. My concern: what is the most efficient way to check the time? Should I just do Thread.sleep for 1 second then update things accordingly? Or should I use Java's date and time classes to do this? If I use the date & time in, say, a while loop, it would be inefficient since I really only need to check to see if something is a new time every second.