无法使用一会儿，或者无法执行... while循环工作，查找了多个答案。什么都行不通

除循环外的所有内容都有效，当被问及是否要再次玩时，输入“ y”或“ n”会引发错误，我一生都无法弄清楚。

对不起，如果此代码格式不正确，请复制并粘贴。

/* © Tucker Fowler 2015
 */
package rpslizardspock;

import java.util.Scanner;
import java.util.Random;

/**
 *
 * @author Tucker
 */
public class RpsLizardSpock {


public static void main(String[] args) {

    String userChoice;
    boolean goAgain;
    boolean y = true;
    boolean n = false;

    Scanner sc = new Scanner(System.in);
    Random ra = new Random();
    while (goAgain = y) {

        System.out.println("Welcome to Rock, Paper, Scissors, Lizard, Spock\n\n"
                + "Please make a Choice: ");
        userChoice = sc.nextLine();

        String ucConv = userChoice.toUpperCase();

        System.out.println("You Chose: " + userChoice);

        int cpuChoice = ra.nextInt(5) + 1;

        if ((cpuChoice == 1) && (((ucConv.equals("LIZARD"))) || ((ucConv.equals("SCISSORS"))))) {
            System.out.println("\n\nComputer chose Rock, You Lose");
        } else if ((cpuChoice == 1) && (((ucConv.equals("PAPER"))) || ((ucConv.equals("SPOCK"))))) {
            System.out.println("\n\nComputer chose Rock, You Win");
        } else if ((cpuChoice == 2) && (((ucConv.equals("SPOCK"))) || ((ucConv.equals("ROCK"))))) {
            System.out.println("\n\nComputer chose Paper, You Lose");
        } else if ((cpuChoice == 2) && (((ucConv.equals("SCISSORS"))) || ((ucConv.equals("LIZARD"))))) {
            System.out.println("\n\nComputer chose Paper, You Win");
        } else if ((cpuChoice == 3) && (((ucConv.equals("LIZARD"))) || ((ucConv.equals("PAPER"))))) {
            System.out.println("\n\nComputer chose Scissors, You Lose");
        } else if ((cpuChoice == 3) && (((ucConv.equals("SPOCK"))) || ((ucConv.equals("ROCK"))))) {
            System.out.println("\n\nComputer chose Scissors, You Win");
        } else if ((cpuChoice == 4) && (((ucConv.equals("SPOCK"))) || ((ucConv.equals("PAPER"))))) {
            System.out.println("\n\nComputer chose Lizard, You Lose");
        } else if ((cpuChoice == 4) && (((ucConv.equals("SCISSORS"))) || ((ucConv.equals("ROCK"))))) {
            System.out.println("\n\nComputer chose Lizard, You Win");
        } else if ((cpuChoice == 5) && (((ucConv.equals("ROCK"))) || ((ucConv.equals("SCISSORS"))))) {
            System.out.println("\n\nComputer chose Spock, You Lose");
        } else if ((cpuChoice == 5) && (((ucConv.equals("PAPER"))) || ((ucConv.equals("LIZARD"))))) {
            System.out.println("\n\nComputer chose Spock, You Win");
        } else if ((cpuChoice == 1) && (ucConv.equals("ROCK"))) {
            System.out.println("\n\nComputer chose Rock also, Draw");
        } else if ((cpuChoice == 2) && (ucConv.equals("PAPER"))) {
            System.out.println("\n\nComputer chose Paper also, Draw");
        } else if ((cpuChoice == 3) && (ucConv.equals("SCISSORS"))) {
            System.out.println("\n\nComputer chose Scissors also, Draw");
        } else if ((cpuChoice == 4) && (ucConv.equals("LIZARD"))) {
            System.out.println("\n\nComputer chose Lizard also, Draw");
        } else if ((cpuChoice == 5) && (ucConv.equals("SPOCK"))) {
            System.out.println("\n\nComputer chose Spock also, Draw");
        }
        System.out.println("\n\n Would you like to play again? y/n");
        goAgain = sc.nextBoolean();
    }
}

}

我得到的错误是：

Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:909)
    at java.util.Scanner.next(Scanner.java:1530)
    at java.util.Scanner.nextBoolean(Scanner.java:1825)
    at rpslizardspock.RpsLizardSpock.main(RpsLizardSpock.java:73)
Java Result: 1