MiscUtils.java:

public static <T, C extends T> void with(T object, Class<C> asCastType, Consumer<C> consumer) {
	consumer.accept((C) object);
}

I can be used like this:

BaseOpeningDay dayToBeSet = new OpeningDay();

MiscUtil.with(dayToBeSet, OpeningDay.class, d -> {
	d.setWeekday(DayOfWeek.SUNDAY);
});

It allows you to both cast and assign at the same time AND it shortens the variable name to the assigned lamda argument name.