Question

I am learning java and started with classes and I am now having some doubts.

I’m going to make a program with data from students, classes and chairs. For example information from the student data will be used in classrooms and chairs. For now, I will restrict myself to the class student.

Each student will have a name and birth date.
I thought I’d create a class with student data and then save the data of students in two arrays. One-dimensional array of strings for the names and an array with three columns for the dates (year, month, day).

I started by creating the Student class with the code:

    public class Stundent{
        private String nameStudent;
        private int yearBirth;
        private int monthBirth;
        private int dayBirth;

        public void setName(String name){
            System.out.println("Insert student's name:");
            nameStudent = name;

        }
        public String getName(){
            return nameStudent;
        }
        public void setYear(int year){
            System.out.println("Insert student's year of birth:");
            yearBirth = year;
        }
        public int getYear(){
            return yearBirth;
        }
        public void setMonth(int month){
            System.out.println("Insert student's month of birth:");
            monthBirth = month;
        }
        public int getMonth(){
            return monthBirth;
        }
        public void setDay(int day){
            System.out.println("Insert student's day of birth:");
            dayBirth = day;
        }
        public int getDay(){
            return dayBirth;
        }
    }

Then in the main file had thought this way:

            Student person = new Student();
            String[] nameStudents = new String[100];
            int[][] birthdayStudents = new int[100][3];
            for (int i = 0; i < 3; i++){

                person.setName(sc.nextLine());
                nameStudents[i] = person.getName();

                person.setAno(sc.nextInt());
                birthdayStudents[i][1] = person.getAno();

                person.setMes(sc.nextInt());
                birthdayStudents[i][1] = person.getMes();

                person.setDia(sc.nextInt());
                birthdayStudents[i][2] = person.getDia();

            }

First question:

Forgetting that this not working properly because the scanner, is this the correct way of thinking?

Second question:

If I run this code I have the following situation:
It will be presented to me “Insert student’s name:” but if I place Maria InputMismatchException will appear. I believe he is storing Maria in the year.
Why does this happen? In the same for cycle I can’t have more than one call to the scanner?
If I only put in the code:

person.setName(sc.nextLine());
nameStudents[i] = person.getName();

and remove everything else concerning the birthday it will work OK.
Can anyone enlighten me?

Answer 1

I think it is not the right way you do it. You mix up the entity Student with input related information. I’d redesign it as follows (a slightly reduced Student):

/* just an entity, no logic at all */
public class Student {
    private String name = null;
    private Integer year = null;

    public void setName(String name){
        this.name = name;
    }

    public void setYear(Integer year){
        this.year = year;
    }
}

And the logic to obtain user input:

List<Student> students = new ArrayList<Student>();
int numberOfStudents = 3;

for (int i = 0; i < numberOfStudents; i++){
    System.out.println("Please enter name:");
    String name = sc.nextLine();

    System.out.println("Please enter year:");
    Integer year = sc.nextInt();

    /* after gathering the input create student */
    Student s = new Student();
    s.setName(name);
    s.setYear(year);

    students.add(s);
}