joe (n.) Look up joe at Dictionary.com
"coffee," by 1941, perhaps late 1930s, of unknown origin. Earlier in American English (1772) it was the colloquial name of a Portuguese or Brazilian coin worth about $8, shortened from Johannes in this sense (1758), the Modern Latin form of Portuguese João (see John), name of a king of Portugual whose head and Latin inscription appeared on the coin.
Joe Look up Joe at Dictionary.com
pet-form of Joseph (q.v.). Meaning "generic fellow, man" is from 1846. Used in a wide range of invented names meaning "typical male example of," for example Joe college "typical college man" (1932); Joe Blow "average fellow" is U.S. military slang, first recorded 1941. "Dictionary of American Slang" lists, among other examples, Joe Average, Beige, Lunch Bucket, Public, Sad, Schmoe, Six-pack, Yale, Zilch