JERSEY CITY — Gregory J. Johnson of Broadway in Bayonne was shot and killed in Jersey City Sunday night. The incident occurred about 8:30 p.m. near Wilkinson and Ocean Avenues. Johnson, 54, was shot in the back during an altercation with a younger man, according to published reports. The Hudson County Prosecutor’s office is asking that anyone with information about the killing call the homicide squad. The Hudson County Prosecutor’s Office Homicide Unit confidential tip line is (201) 915-1345.