code: public final void clear(int field)
      {
          if (areFieldsVirtuallySet) {
              computeFields();
          }
          fields[field] = 0;
          stamp[field] = UNSET;
          isTimeSet = areFieldsSet = areAllFieldsSet = areFieldsVirtuallySet = false;
      }
docs: Clears the value in the given time field.
  @param field the time field to be cleared.