Junior from "Bellboy Donald" and PJ from Goof Troop are the same character
Well, there's at least one fanfic of House of Mouse supporting the theory.- His name would be Pete Junior... which he shortens to PJ as a nickname as a kid. Pretty straightforward and reasonable.
Pete lost his leg in World War I, and became a crook to live after the economic crisis took away his pension
Also, he was reactivated as an instructor during World War II, and was Donald's drill sergeant when a bureaucratic error put him in the US Army for a while (he later returned to the Navy).Pete is actually a crossbreed of a cat and a hippo.
This isn't just a joke about his weight. His mostly hairless muzzle and four large, square teeth
are unusual for a cat, but they would be fitting for a cartoon hippo. See Hyacinth Hippo
◊, for example. Being half-hippo would also explain why he's so vicious and intimidating.