Jewels and Stones

You’re given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones you have are also jewels.

Letters are case sensitive, so “a” is considered a different type of stone from “A”.
Example 1:
　　　Input: jewels = “aA”, stones = “aAAbbbb”
　　　Output: 3

Example 2:
　　　Input: jewels = “z”, stones = “ZZ”
　　　Output: 0

class Solution {
     public int numJewelsInStones(String J, String S) {
    	char[] J_Array = J.toCharArray();
    	char[] S_Array = S.toCharArray();
    	int solution = 0;
    	for(char j_c : J_Array){
    		for(char s_c:S_Array){
    			if(j_c==s_c){
    				solution++;
    			}
    		}
    	}
    	return solution;
    }
}