151. Reverse Words in a String

class Solution {
    public String reverseWords(String s) {
        String[] str = s.split(" ");
        StringBuilder sb = new StringBuilder();
        for(int i = str.length-1 ; i >= 0 ; i--){
            if(str[i] != ""){
                sb.append(str[i]);
                sb.append(" ");
            }
        }
        sb.setLength(sb.length() - 1);
        return sb.toString();
    }
}