One of the things I love about the Internet is the ability to go to blogs from all over the world and read the slang and vocabulary of people from various countries.  I came across an Aussie using "John Barleycorn" and had to look it up.

From Wiki:

John Barleycorn is an English folksong. The character "John Barleycorn" in the song is a personification of the important cereal crop barley, and of the alcoholic beverages made from it, beer and whisky. In the song, John Barleycorn is represented as suffering attacks, death, and indignities that correspond to the various stages of barley cultivation, such as reaping and malting.

Some have interpreted the story of John Barleycorn as representing a pagan practice. It has also been suggested that John Barleycorn, or rather an early form of the song, may have been used by the early church in Saxon England to ease the conversion of pagans to Christianity from their native Anglo-Saxon polytheism. The reasoning behind this idea is that John Barleycorn represented the ideology of nature cycles, spirits and the harvest of the pagan religion (and may have represented human sacrifice also) but that the song was Christianized in order to show John Barleycorn as a Christ-like figure.

Barleycorn, the personification of the barley, encounters great suffering before succumbing to an unpleasant death. However, as a result of this death bread can be produced; therefore, Barleycorn dies so that others may live. Finally his body will be eaten as the bread. Compare this with the Christian concepts of the Sacrament and of Transubstantiation and it is not difficult to imagine how the song might have been beneficial to Christianity. A popular hymn, "We Plough the Fields and Scatter", is often sung at Harvest Festival to the same tune.

As shown above, the point of the tale told by the original versions is twofold: it focuses not only on the death and resurrection of John Barleycorn, but also on Barleycorn's revenge upon the tradesmen who misused him.