- refactor the code and store the session information variables in a Data Transfer Object (DTO)
- when the game starts running, ask the user initially how many players there are playing
- store the number of players in a Map
- run through the Map for each user and let the user have fun playing the game
I think you ought to use an enum for the game. Not only can you say == ROCK, but you can also have loses to paper and wins over scissors in that object. There is a lot of non-object-oriented code in that main method. You should have a Player class with scores as a field. Please search; similar problems come up reasonably frequently.