Deep Thoughts: Cup of Joe edition

This morning I wondered why coffee is also known as "Joe".  I pondered it momentarily and suddenly I had to know.  So I googled "why is coffee called joe".  I found two plausible answers there:

1. Josephus Daniels (18 May 1862-15 January 1948) was appointed Secretary of the Navy by President Woodrow Wilson in 1913. Among his reforms of the Navy were inaugurating the practice of making 100 Sailors from the Fleet eligible for entrance into the Naval Academy, the introduction of women into the service, and the abolishment of the officers' wine mess. From that time on, the strongest drink aboard Navy ships could only be coffee and over the years, a cup of coffee became known as "a cup of Joe". - Big Red on Yahoo! India Answers
2. In 1860 a popular song of the times was "old black Joe" written by Stephen C. Foster the same man who wrote "Camp town races" and "Oh! Suzanna". Diners of the time picked up the slang 'Cup O Joe'.  From Wiki Answers

I guess I'll never really know unless you know a better answer.  Let me know if you know of a reason that coffee is called "Joe".