"i " cannot be resolved as a variable [on hold]

With this section of code I am trying to solve the problem of determining the type of the palindrome and return either “word”, “phrase”, “number”. The definition is number is all digits, a word is all alphabetic, and a phrase is anything else.

I have tried many other ways of accomplishing this and yet I have not been able to make it to where "i" can be resolved as a variable and I do not understand why this is not working.

The program will not compile without this being fixed.

public static String getPalType(String str)
    {   
        int numbers;
        int total;

        for (int i = 0; i < str.length(); i++)
        {
            if (Character.isDigit(str.charAt(i) == true)) // This is where the problem occurs
                {
                    numbers++;
                }
            else
                {
                    return "word";
                }
            if (numbers == total)
                {
                    return "number";
                }
            else
                {
                    return "phrase";
                }
        }