code: public String createPatternString(String pattern, int length) {
          if (pattern == null) {
              return null;
          }
  
          int totalLength = pattern.length() * length;
          StringBuffer sb = new StringBuffer(totalLength);
          for (int i = 0; i < length; i++) {
              sb.append(pattern);
          }
          return sb.toString();
      }
docs: Creates a String with the specified pattern repeated length
  times.