Students class

package com.company;

import java.util.ArrayList;

public class Student {
    private String studentName;
    private int studentLevel;
    private int studentGrade;
    static ArrayList<Student> students = new ArrayList<>();

    public Student(String sn, int sl, int sg){
        setStudentName(sn);
        setStudentLevel(sl);
        setStudentGrade(sg);
    }
    public Student(){

    }

    public void setStudentName(String sn){
        studentName = sn;
    }
    public void setStudentLevel(int sl){
        studentLevel = sl;
    }
    public void setStudentGrade(int sg){
        studentGrade = sg;
    }
    /*public String getStudentName(){
        return studentName;
    }
    public int getStudentLevel(){
        return studentLevel;
    }
    public int getStudentGrade(){
        return studentGrade;
    }*/
    public void addStudent(Student student){ //1
        students.add(student);
    }
    public void update(int index, String name, int level, int grade){ //3
            students.get(index).setStudentName(name);
            students.get(index).setStudentLevel(level);
            students.get(index).setStudentGrade(grade);
    }
    public void remove(int index){ //4
            students.remove(index);
    }
    public void view(String name){ //2
        for(int i=0; i < students.size(); i++){
            if(name.equals(students.get(i).studentName)){
                System.out.println("Name " + students.get(i).studentName);
                System.out.println("Level: " + students.get(i).studentLevel);
                System.out.println("Grade: " + students.get(i).studentGrade);
            }
        }
    }
    public int studentsNumber() {
        return students.size();
    }
}