Java Data Type - 如何将旧的日期/日历/时区类转换为新的Java 8类

import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

public class Main {
  public static void main(String[] argv) {

    Instant instantFromDate = new Date().toInstant();
    
    Instant instantFromCalendar = Calendar.getInstance().toInstant();
    System.out.println(instantFromCalendar);
    
    ZoneId zoneId = java.util.TimeZone.getDefault().toZoneId();
    System.out.println(zoneId);
    
    ZonedDateTime zonedDateTimeFromGregorianCalendar = new GregorianCalendar()
        .toZonedDateTime();

    System.out.println(zonedDateTimeFromGregorianCalendar);
  }
}