表达式的非法开始 - Java

Question

why do I get: illegal start of expression -public static int noOfLetters(String str){ error? and how could I fix it?

public class Mmn15 {

    public static int digInNumFor(int num, int dig) {
        Scanner scan = new Scanner(System.in);
        num = scan.nextInt();
        dig = scan.nextInt();
        int counter = 0;

        for (counter = 0; num > dig;) {
            if (num % 10 == dig); {
                /** reduce  num*/
                num = num / 10;
                counter++;

                return counter;
            }

            // This part is where I get the error:

            public static int noOfLetters(String str){
                Scanner scan = new Scanner(System.in);
                str = scan.nextLine();
                String letter = 0;
                int[] count = new int[letter];

                /** Count array with frequency of characters 
                 */
                int i;
                for (i = 0; i < str.length(); i++)
                    if (str.charAt(i) != ' ')
                        count[(int) str.charAt(i)]++;
                int n = i;

                /** Prints the characters that are more than 0
                 */
                for (i = 0; i < n; i++)
                    if (count[(int) str.charAt(i)] == 1)
                        System.out.print(str.charAt(i));
            }
        }
    }
}

Answer 1

public class Mmn15 {

    public static int digInNumFor(int num, int dig) {
        Scanner scan = new Scanner(System.in);
        num = scan.nextInt();
        dig = scan.nextInt();
        int counter = 0;

        for (counter = 0; num > dig;) {
            if (num % 10 == dig) {
                /** reduce  num*/
                num = num / 10;
                counter++;

                return counter;
            }

            // Method Body ends
         }
            public static int noOfLetters(){
                Scanner scan = new Scanner(System.in);
                String str = scan.nextLine();
                int letter = 26;
                int[] count = new int[letter];

                /** Count array with frequency of characters 
                 */
                int i;
                for (i = 0; i < str.length(); i++)
                    if (str.charAt(i) != ' ')
                        count[str.charAt(i) - 'a']++;
                int n = i;

                /** Prints the characters that are more than 0
                 */
                for (i = 0; i < 26; i++)
                    if (count[(int) str.charAt(i)] >= 1)
                        System.out.print(str.charAt(i));
            }
        }
    }
}