JPA Container many to many problem

I have problem on my application.
When I update its child data.. it successfuly sent to database
But when I access its child data on an Entity Class..
The data doesn't updated..
Also I made my connection with this code

public class AdminHomeView extends Panel implements View {

    
    /**
     *
     */
    private static final long serialVersionUID = 1L;

    public static final String EDIT_ID = "dashboard-edit";
    public static final String TITLE_ID = "dashboard-title";
    
    private EntityManagerFactory emf = Persistence.createEntityManagerFactory(ApplicationUI.JPA);
    private EntityManager em = emf.createEntityManager();
    
    private Label titleLabel;
    private CssLayout dashboardPanels;
    private final VerticalLayout root;

and my Entities are made like this

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

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    
    private String username;
    private String password;
    
    private boolean active;
    
    @Temporal(TemporalType.TIMESTAMP)
    private Date created_at;
    
    @Temporal(TemporalType.TIMESTAMP)
    private Date updated_at;
    
    @ManyToOne
    @JoinColumn(name = "level_id")
    private User_level user_level;
    
    @ManyToMany(targetEntity = System_queries.class)
    private List<System_queries> systemQueriesSet;@Entity
@Table(name = "system_queries")
public class System_queries implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    
    @Column(name = "title")
    private String title;
    @Column(name = "description")
    private String description;
    @Column(name = "statement")
    private String statement;
    
    @Temporal(TemporalType.TIMESTAMP)
    private Date created_at;
    @Temporal(TemporalType.TIMESTAMP)
    private Date updated_at;
    
    @ManyToMany
    @JoinTable(name = "users_system_queries",
            joinColumns={
                    @JoinColumn(name = "systemQueriesSet_ID")
            },
            inverseJoinColumns={
                    @JoinColumn(name = "Users_ID")
            })
    private List<Users> userSet;

My theory is that the data should be updated because each time I change view the Page get Instantiaded again..
But why does the entity child wont be updated?