@Entity
@Table(name = "items")
public class Item extends AbstractModel implements Serializable {
  @Setter private List<Author> authorList;

  @ManyToMany(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH})
  @JoinTable(name = "items_authors",
          joinColumns = @JoinColumn(name = "item_id"),
          inverseJoinColumns = @JoinColumn(name = "author_id"))
  public List<Author> getAuthorList()    { return authorList; }
}

@Entity
@Table(name = "authors")
@NamedQueries({
        @NamedQuery(name = "getAuthorList", query = "SELECT a FROM Author a WHERE 1=1 ORDER BY a.updateTime desc")
})
public class Author extends AbstractModel implements Serializable {
  @Setter private AuthorRole authorRole;
  @Setter private List<Item> itemList;

  @ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH})
  @JoinColumn(name = "author_role_id")
  public AuthorRole getAuthorRole()                       { return authorRole; }

  @ManyToMany(fetch = FetchType.LAZY, mappedBy = "authorList")
  public List<Item> getItemList()                           { return itemList; }
}

@Entity
@Table(name = "author_roles")
@NamedQueries({
        @NamedQuery(name = "getAuthorRoleList", query = "SELECT a FROM AuthorRole a WHERE 1 = 1 ORDER BY a.updateTime desc")
})
public class AuthorRole extends AbstractModel implements Serializable {
  @Setter private List<Author> authorList;

  @OneToMany(mappedBy = "authorRole", cascade = {CascadeType.DETACH})
  public List<Author> getAuthorList()                { return authorList; }
}

@Entity
@Table(name = "items")
public class Item extends AbstractModel implements Serializable {
  @Setter private Map<Author, AuthorRole> authorRoles;

 @ElementCollection 
 @CollectionTable(name="items_authors_roles")
 @MapKeyJoinColumn(name="author_id")
 @Column(name="author_role")  
 public Map<Author, AuthorRole> getAuthorRoles()    { return authorRoles; }
}

ItemDB.findById(1).getAuthorList().get(1).getAuthorRole();

public class ItemId implements Serializable {
 private Set<AuthorRole> ar;
 private Integer id;

  @Override
  public boolean equals(Object obj) {
    return this == obj || obj != null && getClass() == obj.getClass();
  }

  @Override
  public int hashCode() {
    return new HashCodeBuilder(17, 31).append(id).append(ar).toHashCode();
  }

}


@Entity
@IdClass(ItemId.class)
@Table(name = "items")
public class Item extends AbstractModel implements Serializable {
  private List<Author> authorList;
  private Set<AuthorRole> aSet;

  @Override
  @SequenceGenerator(name = "isg", sequenceName = "item_sequence", initialValue = 1, allocationSize = 2)
  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "isg")
  public Integer getId()                 { return super.getId(); }

  @ManyToMany(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH})
  @JoinTable(name = "items_authors",
          joinColumns = @JoinColumn(name = "item_id"),
          inverseJoinColumns = @JoinColumn(name = "author_id"))
  public List<Author> getAuthorList()    { return authorList; }

  @Id
  public Set<AuthorRole> getAuthorRoles()    { return arSet; }
}

ItemDB.findById(1).getAuthorList().get(1).getAuthorRole();

@Entity
@Table(name = "item_author_role")
public class ItemAuthorRole implements Serializable {
  @Getter @Setter @EmbeddedId
  /*@AttributeOverrides({
          @AttributeOverride(name = "itemId", column = @Column(name = "item_id", nullable = false, insertable = false, updatable = false)),
          @AttributeOverride(name = "authorId", column = @Column(name = "author_id", nullable = false, insertable = false, updatable = false)),
          @AttributeOverride(name = "authorRoleId", column = @Column(name = "author_role_id", nullable = false, insertable = false, updatable = false))
  })*/
  private ItemAuthorRoleId id;
  @Setter private Item item;
  @Setter private Author author;
  @Setter private AuthorRole authorRole;

  //@MapsId("itemId")
  @ManyToOne(fetch = FetchType.LAZY)
  //@PrimaryKeyJoinColumn(name = "item_id")
  @JoinColumn(name = "item_id", insertable = false, updatable = false, nullable = false)
  public Item getItem()               { return item; }

  //@MapsId("authorId")
  @ManyToOne(fetch = FetchType.LAZY)
  //@PrimaryKeyJoinColumn(name = "author_id")
  @JoinColumn(name = "author_id", insertable = false, updatable = false, nullable = false)
  public Author getAuthor()           { return author; }

  //@MapsId("authorRoleId")
  @ManyToOne(fetch = FetchType.LAZY)
  //@PrimaryKeyJoinColumn(name = "author_role_id")
  @JoinColumn(name = "author_role_id", insertable = false, updatable = false, nullable = false)
  public AuthorRole getAuthorRole()   { return authorRole; }

  @Override
  public boolean equals(Object obj) {
    return this == obj || obj != null && getClass() == obj.getClass();
  }

  @Override
  public int hashCode() {
    return new HashCodeBuilder(17, 31).append(item).append(author).append(authorRole).toHashCode();
  }
}

@Embeddable
class ItemAuthorRoleId implements Serializable {
  @Getter @Setter @Column(name = "item_id", nullable = false) private Integer itemId;
  @Getter @Setter @Column(name = "author_id", nullable = false) private Integer authorId;
  @Getter @Setter @Column(name = "author_role_id", nullable = false) private Integer authorRoleId;

  @Override
  public boolean equals(Object obj) {
    return this == obj || obj != null && getClass() == obj.getClass();
  }

  @Override
  public int hashCode() {
    return new HashCodeBuilder(17, 31).append(itemId).append(authorId).append(authorRoleId).toHashCode();
  }
}

@Entity
@Table(name = "items")
public class Item extends AbstractModel implements Serializable {
  @Setter private List<Order> orderList;
  @Setter private List<KeyWord> keyWordList;
  @Setter private List<Rubric> rubricList;
  @Setter private Set<ItemAuthorRole> itemAuthorRoleSet;
  @Setter private Set<ItemOrderType> itemOrderTypeSet;
  @Setter private Technic technic;
  @Setter private Era era;
  @Getter @Setter @Embedded private Data data;

  {
    itemAuthorRoleSet = new HashSet<>(0);
    itemOrderTypeSet = new HashSet<>(0);
  }

  @Override
  @SequenceGenerator(name = "isg", sequenceName = "item_sequence", initialValue = 1, allocationSize = 2)
  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "isg")
  public Integer getId()                               { return super.getId(); }

  @ManyToMany(mappedBy = "itemList")
  public List<Order> getOrderList()                    { return orderList; }

  @OneToMany(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH}, mappedBy = "item", targetEntity = ItemAuthorRole.class)
  public Set<ItemAuthorRole> getItemAuthorRoleSet()    { return itemAuthorRoleSet; }

  @OneToMany(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH}, mappedBy = "item", targetEntity = ItemOrderType.class)
  public Set<ItemOrderType> getItemOrderTypeSet()      {  return itemOrderTypeSet; }

  @ManyToMany(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH})
  @JoinTable(name = "items_keyWords",
          joinColumns = @JoinColumn(name = "item_id"),
          inverseJoinColumns = @JoinColumn(name = "keyWord_id"))
  public List<KeyWord> getKeyWordList()                { return keyWordList; }

  @ManyToMany(fetch = FetchType.LAZY, cascade = {CascadeType.DETACH})
  @JoinTable(name = "items_rubrics",
          joinColumns = @JoinColumn(name = "item_id"),
          inverseJoinColumns = @JoinColumn(name = "rubric_id"))
  public List<Rubric> getRubricList()                  { return rubricList; }

  @OneToOne
  @JoinColumn(name = "technic_id")
  public Technic getTechnic()                          { return technic; }

  @OneToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "era_id")
  public Era getEra()                                  { return era; }

  @Version
  @Column(name = "opt_lock")
  private Long version;
}

Exception [EclipseLink-48] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Multiple writable mappings exist for the field [item_author_role.author_id].  Only one may be defined as writable, all others must be specified read-only.
Mapping: org.eclipse.persistence.mappings.OneToOneMapping[author]
Descriptor: RelationalDescriptor(model.item.ItemAuthorRole --> [DatabaseTable(item_author_role)])

Exception [EclipseLink-48] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Multiple writable mappings exist for the field [item_author_role.item_id].  Only one may be defined as writable, all others must be specified read-only.
Mapping: org.eclipse.persistence.mappings.OneToOneMapping[item]
Descriptor: RelationalDescriptor(model.item.ItemAuthorRole --> [DatabaseTable(item_author_role)])