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I have problem when print output list of people by using ArrayList
package data;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;
public class Manager {
List<Person> p = new ArrayList();
Scanner sc = new Scanner(System.in);
public void addStudent() {
String id;
String name;
int yob;
double point1;
double point2;
System.out.println("Input student id:");
id = sc.nextLine();
System.out.println("Input student name:");
name = sc.nextLine();
System.out.println("Input yob:");
yob = Integer.parseInt(sc.nextLine());
System.out.println("Input point 1:");
point1 = Double.parseDouble(sc.nextLine());
System.out.println("Input point 2:");
point2 = Double.parseDouble(sc.nextLine());
p.add(new Student(id,name,yob,point1,point2));
}
public void addEmployee() {
String id;
String name;
int yob;
double salaryRatio;
double salary;
System.out.println("Input employee id:");
id = sc.nextLine();
System.out.println("Input employee name:");
name = sc.nextLine();
System.out.println("Input employee yob:");
yob = Integer.parseInt(sc.nextLine());
System.out.println("Input salary ratio:");
salaryRatio = Double.parseDouble(sc.nextLine());
System.out.println("Input salary:");
salary = Double.parseDouble(sc.nextLine());
p.add(new Employee(id, name, yob,salaryRatio, salary));
}
public void addCustomer() {
String id;
String name;
int yob;
String companyName;
double bill;
System.out.println("Input customer id:");
id = sc.nextLine();
System.out.println("Input customer name:");
name = sc.nextLine();
System.out.println("Input customer yob:");
yob = Integer.parseInt(sc.nextLine());
System.out.println("Input compnay name:");
companyName = sc.nextLine();
System.out.println("Input bill:");
bill = Double.parseDouble(sc.nextLine());
p.add(new Customer(id,name,yob,companyName,bill));
}
public void addWho() {
int choice;
do {
System.out.println("1.Add Student");
System.out.println("2.Add Employee");
System.out.println("3.Add Customer");
System.out.println("4.Back to menu");
System.out.println("==============");
System.out.println("Choice:");
choice = Integer.parseInt(sc.nextLine());
switch(choice) {
case 1:
addStudent();
break;
case 2:
addEmployee();
break;
case 3:
addCustomer();
break;
case 4:
break;
}
}
while(choice != 4);
}
public void printPersonById() {
Collections.sort(p, Comparator.comparing(Person::getId));
for (int i = 0; i < p.size(); i++) {
System.out.println(p.get(i));
}
}
Student,Employee, and Customer are sub classes of class Person.When I try to print list,it has an error:
Exception in thread "main" java.util.IllegalFormatConversionException: d != java.lang.String
How can I fix it?

Try this in your code:
System.out.println("Input yob:");
yob = sc.nextInt();
System.out.println("Input point 1:"); point1 =sc.nextDouble();
System.out.println("Input point 2:"); point2 = sc.nextDouble();
p.add(new Student(id,name,yob,point1,point2));

use System.out.println(p.get(i).someMethodOrVariableOfPerson); instead of System.out.println(p.get(i));
like below
public void printPersonById() {
Collections.sort(p, Comparator.comparing(Person::getId));
for (int i = 0; i < p.size(); i++) {
System.out.println("id :"+p.get(i).id);
System.out.println("name :"+p.get(i).name);
}
}
you can not directly print Person class object in out.println() method.
out.println() allow only string value