code: public static final long currentTimeMillis ()
      {
          long stamp = System.currentTimeMillis();
  
          // on WinXP the time sometimes seems to leap into the past; here
          // we do what we can to work around this insanity by simply
          // stopping time rather than allowing it to go into the past
          if (stamp < _lastStamp) {
              // only warn once per time anomaly
              if (stamp > _lastWarning) {
                  log.warning("Someone call Einstein! The clock is running backwards",
                              "dt", (stamp - _lastStamp));
                  _lastWarning = _lastStamp;
              }
              stamp = _lastStamp;
          }
          _lastStamp = stamp;
  
          return stamp;
      }
docs: Returns {@link System#currentTimeMillis}, but works around a bug on
  WinXP that causes time to sometimes leap into the past.