public class Boxes {
    @Id
    @GeneratedValue
    private Long id;
    @ManyToOne
    private Boards parentBoard;
    @ManyToOne
    private Boxes parentBox; // the root box will have parentBox == null;
    @OneToMany (cascade = CascadeType.REMOVE)
    @JoinTable (name = "Boxes_childboxes", 
            joinColumns = @JoinColumn(name="BoxId"), 
            inverseJoinColumns = @JoinColumn(name="childBoxId")
                )
    private Collection<Boxes> childBoxList = new ArrayList<Boxes>(); // the last leaf box will have childBox == null;
    @OneToMany  (cascade = CascadeType.REMOVE)
    private Collection<Tasks> taskList = new ArrayList<Tasks>();





@Entity
public class Tasks {
    @Id
    @GeneratedValue
    private Long id;
    @ManyToOne
    private Boxes parentBox;
    @ManyToMany
    private Collection<TaskPrivileges> taskPrivilegesList = new ArrayList<TaskPrivileges>();
    @ManyToOne
    private Companies company;
    private String title;
    @Lob
    private String description;
    private String priority; // high , low, critical, normal
    private String status; //completed, working, pending/queued, in problems.
    @ManyToMany 
    private Collection <Users> userList = new ArrayList<Users>();