You can code cleaner, small and reliable with some minimal optimizations, but as long as it remains in main mode will be an imperative program, not an Object Oriented. Object orientation make the aplication scalable with ease.
In the following code you can see that it implements the classic infinite main loop, it is not an error since System.exit calls can break all loops, switch or functions.Also added some code to handle the case when user want to quit without playing.
import java.util.Random;import java.util.Scanner;/** * @author cookiez */public class RockPaperScissors { static int wins = 0; static int losses = 0; static int draws = 0; static int games = 0; private static void lose() { System.out.println("YOU LOSE! :D"); losses++; } private static void win() { System.out.println("you win :D"); wins++; } private static void draw() { System.out.println("Draw"); draws++; } // main method public static void main(String[] args) { Scanner scan = new Scanner(System.in); // variables int user_choice = 0; Random random = new Random(); String answer; int computer_choice; // start of game do { // main menu System.out.println("Input R, P, S, or Q(to quit)."); // player's move answer = scan.next().toLowerCase(); // converts player's move from str to int switch (answer.charAt(0)) { case 'r': user_choice = 0; break; case 'p': user_choice = 1; break; case 's': user_choice = 2; break; case 'q': System.out.println("User exit."); if (games > 0) { double winP = (double) wins / games * 100; double loseP = (double) losses / games * 100; double drawP = (double) draws / games * 100; System.out.printf("Wins: %d \n%.2f Percent\nLosses: %d\n%.2f Percent\nDraws: %d\n%.2f Percent", wins, winP, losses, loseP, draws, drawP); } System.exit(0); default: System.err.println("ERROR!!"); System.exit(1); } // computer's move computer_choice = random.nextInt(3); // (n-1) 0 = rock, 1 = paper, 2 = scissors switch (computer_choice) { case 0: System.out.println("computer chose rock"); break; case 1: System.out.println("computer chose paper"); break; case 2: System.out.println("computer chose scissors"); break; default: System.out.println("ERROR!"); break; } // checks results if (user_choice == computer_choice) { draw(); } else if ((user_choice + 1) % 3 == computer_choice) { lose(); } else { win(); } games++; } while (true); }}