Found the following from africacoffee.com:
<< Two new names which are catching on are "joe" and "hojo." These are not names for ports or for places. The U.S. Navy used to allow alcoholic beverages on U.S. Navy ships. Grog, Ale, and Beer were the supplied as a beverage in the general mess. When Admiral Josephus "Joe" Daniels became Chief of Naval Operations, he outlawed alcohol on board ships. He ordered coffee become the beverage of service on the ships, hence the term "Cup of Joe." Because sailors are generally cold, they wanted their coffee hot. The term hot cup of joe was use, then it was shorten to hot joe, then hojo. >>