default ChronoLocalDateTime plus(TemporalAmount amountToadd)

// Java program to demonstrate
// ChronoLocalDateTime.plus() method
 
import java.time.*;
import java.time.chrono.*;
 
public class GFG {
    public static void main(String[] args)
    {
 
        // Get the ChronoLocalDateTime instance
        ChronoLocalDateTime ldt
            = LocalDateTime
                  .parse("2019-12-31T19:15:30");
 
        // Get the String representation of this ChronoLocalDateTime
        System.out.println("Original ChronoLocalDateTime: "
                           + ldt.toString());
 
        // add 10 Days to ChronoLocalDateTime
        ChronoLocalDateTime value
            = ldt.plus(Period.ofDays(10));
 
        // print result
        System.out.println("ChronoLocalDateTime after adding Days: "
                           + value);
    }
}

Original ChronoLocalDateTime: 2019-12-31T19:15:30
ChronoLocalDateTime after adding Days: 2020-01-10T19:15:30