code: public static Formatter getFormatter()
      {
          Formatter formatter = out.get();
          if (formatter == null)
          {
              formatter = new Formatter(new StringBuilder());
              out.set(formatter);
          }
          else
          {
              StringBuilder sb = (StringBuilder) formatter.out();
              sb.setLength(0);
          }
          return formatter;
      }
docs: Returns thread-local formatter. Inner Appendable is StringBuider which's
  length is set to 0.
  @return