LeetCode irregular brush title --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.

class Solution {

public int lengthOfLastWord(String s) {
    int len=s.length(), lastLength=0;
while(len > 0 && s.charAt(len-1)==' '){
    len--;
}
while(len > 0 && s.charAt(len-1)!=' '){
    lastLength++;
    len--;
}
return lastLength;
}

}