Untitled

package student;

import java.util.HashMap;
import java.util.Map;

public class StudentDatabase {
    private Map<Integer, Student> students = new HashMap<>();
    private int nextId = 1;

    public void addStudent(Student student) {
        student.setId(nextId);
        students.put(nextId, student);
        nextId++;
    }

    public Student getStudent(int i) {
        return students.get(i);
    }

    public void updateStudent(Student retrievedStudent) {
        students.put(retrievedStudent.getId(), retrievedStudent);
    }

    public void listStudents() {
        students.values().forEach(x -> {
            System.out.println(x.toString());
        });
    }
    
}