OneToOne relationship hibernate+spring-data-jpa null value in owning schema

Question

I am new to Hibernate and JPA (I worked mostly with stored procedure integration using JDBC.). I created two entities User and UserPassword with OneToOne relationship. I am trying to store values in both the tables (MySQL DB) but UserId (foreign_key) column of the UserPassword table stores null whereas the password gets stored. Please correct my mistake in below code:

@Entity
@Table(name = "User")
public class User implements Serializable{


    private static final long serialVersionUID = -3366411610525655274L;
    
    @Column(name = "UserId", nullable = false,unique = true)
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    @GeneratedValue(generator = "uuid2")
    @Id
    @Type(type="uuid-char")
    private UUID userId;
    
    @Embedded
    private Name name; 
    
    @Column(name = "DateOfBirth", nullable = false)
    private Date dob;
    
    @OneToOne(mappedBy="user", cascade=CascadeType.ALL)
    private Password password;

    public Password getPassword() {
        return password;
    }

    public void setPassword(Password password) {
        this.password = password;
    }

    public UUID getUserId() {
        return userId;
    }

    public void setUserId(UUID userId) {
        this.userId = userId;
    }

    public Name getName() {
        return name;
    }

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

    public Date getDob() {
        return dob;
    }

    public void setDob(Date dob) {
        this.dob = dob;
    }
    
}

and

@Entity
@Table(name= "UserPassword")
public class Password implements Serializable{

    private static final long serialVersionUID = -8990341903052492314L;

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="PasswordId")
    private Long Id;
    
    @Column(name="Password")
    private String password;
    
    @OneToOne(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
    @JoinColumn(name="UserId", referencedColumnName="UserId")
    private User user;

    public Long getId() {
        return Id;
    }

    public void setId(Long id) {
        Id = id;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    
}

These are the my JPA repositories:

public interface UserRepository extends JpaRepository<User, UUID>{

}

and

public interface PasswordRepository extends JpaRepository<Password, Long>{

}

and service layer code to save entities in database:

public void insertUsers(List<User> users) {
        
        List<com.poc.entity.User> usersData = ObjectMapperUtils.mapAll(users, com.poc.entity.User.class);
        
        userRepository.saveAll(usersData);
    }

Also, please help me in proper designing approach for this work.

Answer 1

It worked by doing small modification in service layer logic.

 public void insertUsers(List<User> users) {
        
        List<com.poc.entity.User> usersData = ObjectMapperUtils.mapAll(users, com.poc.entity.User.class);
            
        usersData = usersData.stream().map(user->mapUserPassWordEntity(user)).collect(Collectors.toList());
        
        userRepository.saveAll(usersData);
    }

    private com.poc.entity.User mapUserPassWordEntity(com.poc.entity.User user) {
        Password password = new Password();
        password.setPassword(user.getPassword().getPassword());
        //set parent reference to child
        password.setUser(user);
        // set child reference to parent
        user.setPassword(password);
        return user;
    }

Still, I would appreciate more suggestions for better approach.