Backwards Logic?

public static final int MAX_MISSES = 7;
private String answer;
private String hits;
private String misses;

private char normalizeGuess(char letter){
    // Check if user input is not a letter
    if (! Character.isLetter(letter)) {
        throw new IllegalArgumentException("A letter is required");
    }
    letter = Character.toLowerCase(letter);
    // Apply check to see if letter has already been guessed
    if (misses.indexOf(letter) != -1 || hits.indexOf(letter) != -1) {
        throw new IllegalArgumentException(letter + " has already been guessed");
    }
    return letter;
}

// Constructor for answer
public Game(String answer) {
    this.answer = answer.toLowerCase();
    hits = "";
    misses = "";
}

// Method to apply guess towards answer
public boolean applyGuess(char letter){
    letter = normalizeGuess(letter);
    boolean isHit = answer.indexOf(letter) != -1;
    if (!isHit) {
        hits += letter;
    }else {
        misses += letter;
    }
    return isHit;
}

public int getRemainingTries(){
    return MAX_MISSES - misses.length();
}

// Method that will return a string and show dashes for unguessed letters
public String getCurrentProgress(){
    String progress = "";
    for (char letter : answer.toCharArray()) {
        char display = '_';
        if (hits.indexOf(letter) != -1) {
            display = letter;
        }
        progress += display;
    }
    return progress;
}

// Prompt user for input by storing instance of game inside variable
private Game game;

public Prompter(Game game){
    this.game = game;
}

public boolean promptForGuess(){
    Scanner scanner = new Scanner(System.in);
    boolean isHit = false;
    // Store new value to keep track of state
    boolean isAcceptable = false;
    // Loop to keep checking if input is valid
    do {
        // Prompt user for input
        System.out.println("Enter a letter:  ");
        // Get input
        String guessInput = scanner.nextLine();
        char guess = guessInput.charAt(0);
        try{
            // Normalize user input
             isHit = game.applyGuess(guess);
             // Change value to true
             isAcceptable = true;
            }catch(IllegalArgumentException iae){
                System.out.printf("%s.  Please try again. ",
                    iae.getMessage());
        }
    }while(! isAcceptable);
    return isHit;
}

public void displayProgress(){
    System.out.printf("You have %d tries left to solve:  %s%n ",
                        game.getRemainingTries(), 
                        game.getCurrentProgress());
}