DayOfWeek Sınıfı

from metodu
Şöyle yaparız.

DateTimeFormatter dtf = DateTimeFormatter.ofPattern("ccc", Locale.GERMAN);
DayOfWeek mo = dtf.parse("Mo", DayOfWeek::from);

plus metodu 

Örnek

Şöyle yaparız

DayOfWeek dayOfWeek = DayOfWeek.TUESDAY;
DayOfWeek dayOfWeek1 = dayOfWeek.plus(10);
System.out.println(dayOfWeek1); // FRIDAY