code: public final ReadOnlyObjectProperty<LocalTime> startTimeProperty() {
          if (startTime == null) {
              startTime = new ReadOnlyObjectWrapper<>(this, "startTime", getInterval().getStartTime()); //$NON-NLS-1$
          }
          return startTime.getReadOnlyProperty();
      }
docs: A read-only property used for retrieving the start time of the entry. The
  property gets updated whenever the start time inside the entry interval
  changes (see {@link #intervalProperty()}).
  
  @return the start time of the entry