code: public String print(ReadableInstant instant) {
          StringBuilder buf = new StringBuilder(requirePrinter().estimatePrintedLength());
          try {
              printTo((Appendable) buf, instant);
          } catch (IOException ex) {
              // StringBuilder does not throw IOException
          }
          return buf.toString();
      }
docs: Prints a ReadableInstant to a String.
  <p>
  This method will use the override zone and the override chronology if
  they are set. Otherwise it will use the chronology and zone of the instant.
  
  @param instant  instant to format, null means now
  @return the printed result