Reverse words in a String

/*
 * tricky part: the last append(" ") needs to be deleted if this is the last word
 */
public class Reverse_words_in_a_string {
 public static String reverseWords1(String s) {
  if (s == null || s.length() == 0) {
   return "";
  }
  String[] arrayStr = s.split(" ");
  int length = arrayStr.length;

     StringBuffer newStr = new StringBuffer();
  for (int i = length - 1; i >= 0; i--) {
   if (!arrayStr[i].trim().equals("")) {
    newStr.append(arrayStr[i].trim()).append(" ");
   }
   
  }
  // the last " "(space) needs to be deleted
  return newStr.length() == 0 ? "": newStr.substring(0, newStr.length() - 1);

    }