Handel and implement two type of user in hibernate, spring boot and security

i'm a beginner to spring boot and hibernate, i'm doing my first app and i have a problem in designing relations in hibernate I have two users (Advertiser and Student) both have shared properties but differ in one, that advertiser belong to organization but student belong to a university (relation shown in database diagram below)

i have tried to do a user class, and but a reference to Advertiser and Student on it, with Featch-Type-LAZY , so i check the type of user, when it is advertiser, get advertiser object, otherwise student one code below - but i'm confused about is that the right way to implement different user type in hibernate? - is it a good design for code according to design-pattern principle ? - and if i want to make User class @Embaddable and make Advertiser and Student inherit it, so that i get rid of User table in database, then in spring security i have to make to access two table to get the user, will be that be better than before?

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

    @Column(nullable = false) @Enumerated(EnumType.STRING)
    private AccountState state;

    @Column(nullable = false) @Enumerated(EnumType.STRING)
    private UserType type;

    @Column(nullable = false)
    private String firstName;

    @Column(nullable = false)
    private String lastName;

    @Column(nullable = false, unique = true)
    private String email;

    @Column(nullable = false) @Temporal(TemporalType.DATE)
    private Date birthday;

    @Column(nullable = false)
    private String password;

    @Transient
    private String confirmPass;

    @OneToOne(mappedBy = "user", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    private Advertiser advertiser;

    @OneToOne(mappedBy = "user", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    private Student student;

// setters and getters 
}

@Entity
public class Advertiser {

    @EmbeddedId
   private AdvertiserId advertiserId;

    @OneToOne
    @JoinColumn(name = "user_id", insertable = false, updatable = false)
    private User user;

    @ManyToOne
    @JoinColumn(name = "organization_id", insertable = false, updatable = false)
    private Organization organization;

// setter and getter 
}

@Entity
public class Student{

    @EmbeddedId
    private StudentId studentId;


    @OneToOne
    @JoinColumn(name = "user_id", insertable = false, updatable = false)
    private User user;

    @ManyToOne
    @JoinColumn(name = "university_id", insertable = false, updatable = false)
    private University university;

    // setter and getter
    }