docs: public static String repeat(String s, Integer count) {
  
          if (s == null || count == null || count.intValue() < 0) {
              return null;
          }
  
          int          i  = count.intValue();
          StringBuffer sb = new StringBuffer(s.length() * i);
  
          while (i-- > 0) {
              sb.append(s);
          }
  
          return sb.toString();
      }