See quotations.
1838. Before me, though at the head of many delicacies provided by papa, was an immense field of hopping John; a good dish, to be sure, but no more presentable to strangers at the South than baked beans and pork in New-England. [Note] Bacon and rice.Caroline Gilman, Recollections of a Southern Matron, p. 124. (Italics in the original.)
1856. The greatest luxury with which they [the people along the Congaree River, S.C.] are acquainted is a stew of bacon and peas, with red pepper, which they call Hopping John.Olmsted, Slave States, p. 506. (N.E.D.)
[1830. The same phrase appears to have a different meaning in England: What dye say to Hopping John, made Tom Nottles fashion?Landlord, mix pint of brandy wi half a gallon of your best cider, sugared to your own taste; and pop in about a dozen good roasted apples, hissing hot, to take the chill off.George Cruikshanks Three Courses and a Dessert, p. 26.]