Justice was a title bestowed upon a senior officer who was serving as a judge within the Court at Starfleet Headquarters on Earth.
In 2384, three Justices presided over the case of a group of young aliens who "stole" the USS Protostar and violated several Starfleet regulations. (PRO: "Supernova, Part 2")
While not directly mentioned in "Supernova, Part 2", the title is featured in the episode's end credits.