leetcode771(java) Jewels and Stones

public int numJewelsInStones(String J, String S) {
        int result = 0;
        char[] j = J.toCharArray();
        char[] s = S.toCharArray();
        for(int a=0;a<j.length;a++){
            for(int b=0;b<s.length;b++){
                if(s[b]==j[a]){
                    result++;
                }
            }
        }
        return result;
    }