code: protected boolean isAllWhiteSpace(CharSequence sb) {
          boolean result = true;
          for (int i = 0; i < sb.length(); i++) {
              char c = sb.charAt(i);
  
              if (!Character.isWhitespace(c)) {
                  return false;
              }
          }
          return result;
      }
docs: precondition: sb.length() > 0
  
  @param sb A sequence of characters to examine
  @return true if every character in the sequence is whitespace