There is definitely a difference between justice and revenge :)
Justice means fair behavior or treatment, or something that’s fair in general, while revenge means getting back at someone, whether it’s fair or not. So there can be justice in revenge, but there can’t be revenge in justice. For example, if someone killed your mother or your best friend, calling the cops and putting them in jail is justice, while killing them back is revenge. Now you might have a question—killing them back is fair right, since they killed your beloved ones? Not necessarily since justice also means a sense of morality and humanity, and it’s not really moralistic or humane for you to kill them back. Therefore, there can be justice in revenge because putting them in jail would prevent them from killing anyone else, but there can’t be revenge in justice cause murdering the murderer is not fair, for you’ll become a murderer then, too.