Как работать с классом period в java

import java.time.LocalDate;
import java.time.Period;

public class App {
    public static void main(String[] args) {
        LocalDate startDate = LocalDate.now()
                .minusYears(1).minusWeeks(1);
        LocalDate endDate = LocalDate.now()
                .plusMonths(3).plusDays(4);

        Period period = Period.between(startDate, endDate);
        System.out.println(period); // => P1Y3M11D

        period = period.plusDays(5);
        System.out.println(period.getDays()); // => 16

        period = Period.of(5,2,3);
        System.out.println(period); // => P5Y2M3D
    }
}