I disagree...the key difference is with intent, not with morality, merit, or impartiality... We can certainly point out that justice concerns the proper punishment for bad behavior while revenge can be any kind of punishment for any perceived slight. If that’s the only difference, however, then it seems that justice is merely a type of revenge. I propose a further difference, which concerns virtue ethics: true justice is motivated by the desire to establish a better society; revenge is motivated by the desire to harm. That is, of course, if we actually wish to make justice a noble pursuit instead of an expression of barbarism that conveniently has some social benefit.