Leetcode-Length of Last Word

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example,
Given s = "Hello World",
return 5.

Solution:

public class Solution {
    public int lengthOfLastWord(String s) {
        s = s.trim();
        int index = s.length()-1;
        while (index>=0 && s.charAt(index)!=' ') 
            index--;
        return (s.length()-index-1);        
    }
}