code: public static String presentTimestamp(long timestamp) {
  		if (timestamp == 0) {
  			return UNDEF_STRING;
  		}
  		synchronized (TIMESTAMP_FORMAT) {
  			return TIMESTAMP_FORMAT.format(new Date(timestamp));
  		}
  	}
docs: Returns timestamp in human readable (yet condensed) form "yyMMdd-HHmmss.SSS".
  
  @param timestamp timestamp in millis
  @return timestamp as a human readable string