Using constructor and using set () for same attributes

I am studying JPA following the example of uaiContacts .

His project is in GitHub.

I took the example of the modelContact.java file:

The Contact class is mapped:

public class Contact {
    @Id
    @GeneratedValue
    private int id;
    private String name;
    private String phoneNumber;
    private String email;
}

and it uses a constructor.

public Contact(String name, String phoneNumber, String email, int id) {
    super();
    this.name = name;
    this.phoneNumber = phoneNumber;
    this.email = email;
}

It uses set .

The question is: Why does it get get and set ? If the constructor already sets these values when defining an object.

Maybe you should not only use get ?

Comments:

Has no inheritance to initialize the constructor; So I do not understand super() , since it has no parent class or maybe some other project class extends this class.

Complete model contact. model / Contact.java

package uaiContacts.model;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Contact {

    @Id
    @GeneratedValue
    private int id;
    private String name;
    private String phoneNumber;
    private String email;

    public Contact(){

    }

    public Contact(String name, String phoneNumber, String email, int id) {
        super();
        this.name = name;
        this.phoneNumber = phoneNumber;
        this.email = email;
    }

public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

@Override
    public boolean equals(Object object) {
        if (object instanceof Contact){
            Contact contact = (Contact) object;
            return contact.id == id;
        }

        return false;
    }

    @Override
    public int hashCode() {
        return id;
    }
}

Take, if you prefer, the code in gitHub:

link