public ChronoZonedDateTime plus(TemporalAmount amountToadd)

// Java program to demonstrate
// ChronoZonedDateTime.plus() method
 
import java.time.*;
import java.time.chrono.*;
import java.time.temporal.ChronoUnit;
 
public class GFG {
    public static void main(String[] args)
    {
 
        // create a ChronoZonedDateTime object
        ChronoZonedDateTime zonedlt
            = ZonedDateTime
                  .parse(
                      "2018-12-06T19:21:12.123+05:30[Asia/Calcutta]");
 
        // add 10 Days to ChronoZonedDateTime
        ChronoZonedDateTime value
            = zonedlt.plus(Period.ofDays(10));
 
        // print result
        System.out.println("ChronoZonedDateTime after"
                           + " adding Days:\n "
                           + value);
    }
}

ChronoZonedDateTime after adding Days:
 2018-12-16T19:21:12.123+05:30[Asia/Calcutta]