code: private void writeObject(ObjectOutputStream stream)
              throws IOException
              {
          // Try to compute the time correctly, for the future (stream
          // version 2) in which we don't write out fields[] or isSet[].
          if (!isTimeSet) {
              try {
                  updateTime();
              }
              catch (IllegalArgumentException e) {}
          }
  
          // Write out the 1.1 FCS object.
          stream.defaultWriteObject();
              }
docs: Save the state of this object to a stream (i.e., serialize it).