JPA ManyToMany error when persistance

Question

I get an error when i use ManyToMany relationship to persist an object, I searched a lot about this problem but I can't find the solution, someone help me to find a solution for this problem please, here is my code :

Utilisateur entity

public class Utilisateur implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(nullable = false)
    private Integer id;
    @Column(length = 2147483647)
    private String nom;
    private Integer theme;
    @JoinTable(name = "utilisateur_prvilege", schema = "sch_admin", joinColumns = {
        @JoinColumn(name = "privilege", referencedColumnName = "id")}, inverseJoinColumns = {
        @JoinColumn(name = "utilisateur", referencedColumnName = "id")})
    @ManyToMany(cascade = CascadeType.ALL)
    private List<Privilege> privilegeList = new ArrayList<>();

..getters and setter..

}

Privilege entity

public class Privilege implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column
    private Integer id;
    private Integer pane;
    @Column(length = 2147483647)
    private String description;
    @ManyToMany(mappedBy = "privilegeList")
    private List<Utilisateur> utilisateurList = new ArrayList<>();
..getters and setter..

}

Create new Utilisateur

public void create(Utilisateur utilisateur) {
    EntityManager em = null;
    try {
        em = getEntityManager();
        em.getTransaction().begin();
        em.persist(utilisateur);
        em.getTransaction().commit();
    } finally {
        if (em != null) {
            em.close();
        }
    }
}

Answer 1

In

@ManyToMany(mappedBy = "privilegeList")
private List<Utilisateur> utilisateurList = new ArrayList<>(); 

add cascadettype property and give value to persist.

Answer 2

You need to make a small change in the ManyToMany annotation. You are defining the ManyToMany mapping in Utilisateur but your join column(not inverse mapping) is privilege instead of utilisateur . Make these changes and it should work now.

public class Utilisateur implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(nullable = false)
private Integer id;
@Column(length = 2147483647)
private String nom;
private Integer theme;
@JoinTable(name = "utilisateur_prvilege", schema = "sch_admin", joinColumns = {
    @JoinColumn(name = "utilisateur", referencedColumnName = "id")}, inverseJoinColumns = {
    @JoinColumn(name = "privilege", referencedColumnName = "id")})
@ManyToMany(cascade = CascadeType.ALL)
private List<Privilege> privilegeList = new ArrayList<>();

..getters and setter..

}

add em.flush(); line before commit and check

Many To Many mapping Tutorial link .