To Generate the non-repeated characters of String. Given two integers X and Y, returns containing exactly X letters "A" and exactly Y letters "b". X defines maximum of character repetition.

NonRepeatCharacters.Java

public class NonRepeatCharacters {
    public static void main(String[] args) {
        System.out.println("Answer is " + NonRepeatString(2, 5, 3));
    }

    // n = Maximum number of repeation;
    // x = 1st character with number of times.
    // y  -2nd character with number of times.
    public static String NonRepeatString(int n, int X, int Y) {
        String biggerString, smallerString;
        int biggerCount, smallerCount;
        if (n > X || n > Y) {
            return "Invalid Solution";
        }

        if (X >= Y) {
            biggerString = "A";
            smallerString = "b";
            biggerCount = X;
            smallerCount = Y;
        } else {
            biggerString = "b";
            smallerString = "A";
            biggerCount = Y;
            smallerCount = X;
        }
        // A > NB + N
//        if (biggerCount > 2 * smallerCount + 2) {
        if (biggerCount > ((n * smallerCount) + n)) {
            return "Invalid Value Entry";
        }

        StringBuilder returnString = new StringBuilder();
        do {
            if (biggerCount == smallerCount + (n - 1)) {
                returnString.append(biggerString);
                biggerCount--;
            } else if (biggerCount == smallerCount) {
                returnString.append(biggerString);
                biggerCount--;
                returnString.append(smallerString);
                smallerCount--;
            } else {
                int nFinal = 0;
                if (n < biggerCount) {
                    nFinal = n;
                } else {
                    nFinal = biggerCount;
                }

                for (int i = 0; i < nFinal; i++) {
                    returnString.append(biggerString);
                }
                biggerCount -= n;
                if (smallerCount > 0) {
                    int sFinal = 0;
                    if(n<=smallerCount){
                        sFinal = n-1;
                    }else{
                        sFinal = smallerCount;
                    }
                    
                    for (int j = 0; j <sFinal; j++) {
                        returnString.append(smallerString);
                    }
                    smallerCount -= n-1;
                }
            }
        } while (biggerCount > 0);
        return returnString.toString();
    }
}