Finding four of a kind in a 5 card game

Question

I am trying to find four of kind in a 5 poker hand. I don't know where I went wrong, but the JUnit is reporting it's wrong.

public boolean hasFourOfaKind(String hand) {
    int counter = 0;
    char x = 0;

    for (int i = 0; i < hand.length(); i++) {
        for (int j = 0; j < hand.length(); j++) {
            if (i == 0) {
                x = hand.charAt(0);
                counter++;
            } else if (x == hand.charAt(i)) {
                counter++;

            }
        }
    }
    if (counter >= 4) {
        return true;
    } else {
        return false;
    }
}

Answer 1

Your loop logic is wrong. It is incrementing counter for the same card again. That's why it is failing. In below mentioned code I am considering card only once.

public static boolean hasFourOfaKind(String hand) {
    int counter = 0;
    for (int i = 0; i < hand.length(); i++) {
        counter = 0;
        for (int j = 0; j < hand.length(); j++) {
            if (hand.charAt(j) == hand.charAt(i)) {
                counter++;
            }
        }
        if (counter >= 4) {
            return true;
        }
    }
    return false;
}