Warrior's Quest [Java]

import java.util.Scanner;

public class EXAM_Retake_13_Dic_2019 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        String input = scan.nextLine();

        while (true) {
            String line = scan.nextLine();

            if ("For Azeroth".equals(line)) {
                break;
            }

            String[] tokens = line.split("\\s+");

            switch (tokens[0]) {
                case "GladiatorStance":
                    input = input.toUpperCase();
                    System.out.println(input);
                    break;

                case "DefensiveStance":
                    input = input.toLowerCase();
                    System.out.println(input);
                    break;

                case "Dispel":
                    int index = Integer.parseInt(tokens[1]);
                    char toUse = tokens[2].charAt(0);

                    if (index >= 0 && index < input.length()) {
                        StringBuilder sb = new StringBuilder(input);
                        sb.setCharAt(index, toUse);
                        input = sb.toString();
                        System.out.println("Success!");
                    } else {
                        System.out.println("Dispel too weak.");
                    }

                    break;

                case "Target":
                    String whatToDo = tokens[1];
                    String SubstringToQuit = tokens[2];

                    if (whatToDo.equals("Change")) {
                        String substringToPut = tokens[3];

                        input = input.replace(SubstringToQuit, substringToPut);

                        System.out.println(input);
                    } else if (whatToDo.equals("Remove")) {
                        input = input.replace(SubstringToQuit, "");

                        System.out.println(input);
                    } else {
                        System.out.println("Command doesn't exist!");
                    }

                    break;

                default:
                    System.out.println("Command doesn't exist!");
            }
        }
    }
}