FRQ code that doesn't work

import static java.lang.Math.*;
import static java.lang.System.*;

public class test {
    public static void main (String[] args) {
        String str = "CCAAAAATTT!";
        int counter1 = 0, counter2 = 0;
        char firstChar = 0, secondChar = 0;

        for (int i = 0; i < str.length(); i++) {
            if (i + 2 > str.length()) {
                if (str.charAt(i) == str.charAt(i-1)) {
                    counter1++;
                    firstChar = str.charAt(i);
                }
            }
            else if ((str.charAt(i) == str.charAt(i + 1)) || str.charAt(i) == str.charAt(i - 1)) {
                counter1++;
                firstChar = str.charAt(i);
            }
            if (counter1 > counter2) {
                counter2 = counter1;
                counter1 = 0;
                secondChar = firstChar;
                firstChar = 0;
            }
        }
        System.out.println(secondChar + " " + counter2);
    }
}