Longest Common Substring

public class Solution {
    /**
     * @param A, B: Two string.
     * @return: the length of the longest common substring.
     */
    public int longestCommonSubstring(String aA, String aB) {
        if (aA.isEmpty() || aB.isEmpty()){
            return 0;
        }
        char[] charA = aA.toCharArray();
        char[] charB = aB.toCharArray();
        int cubString = 0;
        for (int i = 0; i < aA.length(); i++){
            for (int j = 0; j < aB.length(); j++){
                int tempCubString = 0;
                while ((j + tempCubString < aB.length()) && (i + tempCubString < aA.length())
                    && charA[i + tempCubString] == charB[j + tempCubString]){
                    tempCubString++;
                }
                if (tempCubString > cubString){
                    cubString = tempCubString;
                }
            }
        }
        return cubString;
    }
}