[Java Calculate Hamming distance] Calculating the Hamming Distance for two strings of the same length #Java

HammingDist.java

// adapted from here: https://stackoverflow.com/questions/16260752/using-for-loop-to-get-the-hamming-distance-between-2-strings

public class Hamming
{
    private String compOne;
    private String compTwo;
 
    public Hamming(String one, String two)
    {
        compOne = one;
        compTwo = two;
    }
 
    ///
    //  Calculating the Hamming Distance for two strings requires the string to be of the same length.
    ///
    public int getHammingDistance()
    {
        if (compOne.length() != compTwo.length())
        {
            return -1;
        }
 
        int counter = 0;
 
        for (int i = 0; i < compOne.length(); i++)
        {
            if (compOne.charAt(i) != compTwo.charAt(i)) counter++;
        }
 
        return counter;
    }
 
    ///
    //  Hamming distance works best with binary comparisons, this function takes a string arrary of binary
    //  values and returns the minimum distance value
    ///
    public int minDistance(String[] numbers)
    {
        int minDistance = Integer.MAX_VALUE;
 
        if (checkConstraints(numbers))
        {
            for (int i = 1; i < numbers.length; i++)
            {
                int counter = 0;
                for (int j = 1; j <= numbers[i].length(); j++)
                {
                    if (numbers[i-1].charAt(j-1) != numbers[i].charAt(j-1))
                    {
                        counter++;
                    }
                }
 
                if (counter == 0) return counter;
                if (counter < minDistance) minDistance = counter;
            }
        }
        else
        {
            return -1;
        }
 
        return minDistance;
    }
 
    private Boolean checkConstraints(String[] numbers)
    {
        if (numbers.length > 1 && numbers.length <=50)
        {
            int prevLength = -1;
            for (int i = 0; i < numbers.length; i++)
            {
                if (numbers[i].length() > 0 && numbers[i].length() <= 50)
                {
                    if (prevLength == -1)
                    {
                        prevLength = numbers[i].length();
                    }
                    else
                    {
                        if (prevLength != numbers[i].length())
                        {
                            return false;
                        }
                    }
 
                    for (int j = 0; j < numbers[i].length(); j++)
                    {
                        if (numbers[i].charAt(j) != '0' && numbers[i].charAt(j) != '1')
                        {
                            return false;
                        }
                    }
                }
                else
                {
                    return false;
                }
            }
        }
        else
        {
            return false;
        }
 
        return true;
    }
}