Don’t worry, DateTime is a very sensitive topic => DateTime Conversion (openHAB 3.x)
Let me try to break it down
tomorrowDateTime = time.ZonedDateTime.now().plusDays(1); // tomorrow as js-joda
tomorrowDate = time.convert(tomorrowDateTime).toDate(); // convert to javascript date
forecastTomorrow = solareForecastActions.getDay(tomorrowDate);
time.
is referring to js-joda library like described in javascript bindingtomorrowDateTime
is exactly one day ahead as joda objecttomorrowDate
is the conversion from js-joda to javascript date- use this
tomorrowDate
to query forecast for next day