Dear Experts,
How to convert list of entites to Json string?
entity1:
@Entity
@NamedQueries({ @NamedQuery(name = "Departament.findAll", query = "select o from Departament o"))
@Table(name = "DEPARTMENT")
public class Departament implements Serializable {
@Id
@Column(nullable = false)
private Long id;
@Column(length = 119)
private String name;
@OneToMany(mappedBy="department", cascade = { CascadeType.PERSIST, CascadeType.MERGE })
private List<AccessRights> perms;
// cut: setters and getters
entity 2:
@Entity
@Table(name = "ACCESS_RIGHTS")
public class AccessRights implements Serializable {
@Id
@Column(nullable = false)
private Long id;
@ManyToOne
@JoinColumn(name = "ID_JEDNOSTKA")
private Departament department;
// cut: setters and getters
In my main class I have executed:
List<Departament> vl = ac.getDepartament();
System.out.println(new Gson().toJson(vl).toString()); //error: "An attempt was made to traverse a relationship using indirection that had a null Session."
The has started to orccured when I've created ManyToOne relationship. If I remove it, everything works.
I assume that toJson method cannot be applied. If there is any relation between entities.
I'm I correct? How such an issue can be resolved?
I've tried other parsers like Objectmapper, JsonLib - no success.
Best regards.