I am working on the Longest Common Prefix (LCP) problem in leetcode where you have to build a program that compares different strings in an array and look for the LCP if any. I am getting the error: “cannot find symbol” in line 10 of my code.

So far, I am trying a brute force approach, where I use the first string in the array to compare each character within the array at the same index. Once a characters differs I know it is not part of the LCP. Here is my code so far:

class Solution {

    public String longestCommonPrefix(String[] strs) {
        char checkingChar;
        String prefix;
        Boolean isPrefix;
        String firstWord;

        for (int i = 0; i < strs[0].length(); i++) {
            checkingChar = strs[0].get(i);


            isPrefix = true;
            for (int j = 0; i < strs.length; j++) {
                if (strs[j].charAt(i) != checkingChar) {
                    isPrefix = false;
                }
            }
            if (isPrefix == true) {
                prefix += checkingChar;
            }
        }
        return prefix;
    }
}