Length of Last Word Total

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.

Naive Way: This question is relatively easy. The edge case is the testing point. All the edge case I can came up with are,

• ""
• " "
• "   "
• "word  "
• "word"

So, basically keep two pointers and eliminate all tailing white-spaces.

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