LeetCode: Jewels and Stones

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

The letters in J are guaranteed distinct, and all characters in J and S are letters. Letters are case sensitive, so "a" is considered a different type of stone from "A".

Example 1:

Input: J = "aA", S = "aAAbbbb"
Output: 3

Example 2:

Input: J = "z", S = "ZZ"
Output: 0

Note:

• S and J will consist of letters and have length at most 50.
• The characters in J are distinct.

public class Solution
{
    public static int numJewelsInStones(String J, String S) {
        int count = 0;
        for (char c : S.toCharArray()) {
            if (J.indexOf(c) != -1 ) {
                count++;
            }
        }
        return count;    
    }
    public static void main(String[] args) {
        String Jewels = "abC";
        String Stones = "aAbCAAbBBBB";
        System.out.println ("Number of Jewels : " + numJewelsInStones(Jewels,Stones));
    }
}