Не инициализируються объекты класса

import java.util.*;
 
public class Main{
    public static void main(String[] args) {
        Calendar calendar = new GregorianCalendar(2021, 8 , 15);
        Calendar calendar1 = new GregorianCalendar(2021, 6 , 8);
        Calendar calendar2 = new GregorianCalendar(2021, 8 , 4);
        Buyer person = new Buyer("Igor",calendar, "380932744474",1000);
        Buyer person1 = new Buyer("Lutor",calendar1, "380932744474",200);
        Buyer person2 = new Buyer("Sony",calendar2, "380932744474",700);
        
        System.out.println(person.getPrice() +" "+ person.getFullName() +" "+ person.getDateOfPurchase());
 
        Buyer[] persons = new Buyer[3];
        persons[0] = person;
        persons[1] = person1;
        persons[2] = person2;
 
        for (Buyer pers:
             persons) {
            System.out.println(pers);
        }

import java.util.*;
 
public class Buyer {
  private  String fullName;
  private Calendar dateOfPurchase;
  private String phoneNum;
  private int price;
  private boolean active;
 
    public Buyer(String fullName, Calendar dateOfPurchase, String phoneNum, int price){
        fullName = this.fullName;
        dateOfPurchase = this.dateOfPurchase;
        phoneNum = this.phoneNum;
        price = this.price;
        System.out.println("Покупатель добавлен!");
    }
 
    public int getPrice() {
        return price;
    }
 
    public Calendar getDateOfPurchase() {
        return dateOfPurchase;
    }
 
    public String getFullName() {
        return fullName;
    }
 
    public void setDate(Calendar dateOfPurchase){
        dateOfPurchase = this.dateOfPurchase;
    } 
   @Override
    public String toString() {
        return "Name: "+this.fullName + ", "+ "Phone number: " + "(" + this.phoneNum + ")" + ", " + this.price;
              //  new SimpleDateFormat("dd.MM.yyyy").format(getDateOfPurchase().getTime());
    }
}