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POObjectDB, failed to write the value of field (error 363)
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  1. POObjectDB, failed to write the value of field (error 363)
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    copied!<p>I'm trying to make an application that can store a tree structure with files and folders in an ObjectDB database (embedde), but even with a simple test I keep getting an error...</p> <h2>Entity classes</h2> <p><strong>Node.java</strong></p> <pre><code>@MappedSuperclass public abstract class Node { @Column(name = "Name", nullable = false) private String name; @Column(name = "Parent_FK") @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "FolderID", nullable = true) private FolderNode parent = null; public Node() { } public Node(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } public boolean hasParent() { return (parent != null); } public FolderNode getParent() { return parent; } void setParent(FolderNode parent) { this.parent = parent; } @Override public int hashCode() { return new HashCodeBuilder(17, 31).append(name).toHashCode(); } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (obj == this) { return true; } if (obj instanceof Label) { // TODO is instanceof enough?? Label other = (Label) obj; return name.equals(other.getName()); } return false; } } </code></pre> <p><strong>FolderNode.java</strong></p> <pre><code>@Entity(name = "Folders") public class FolderNode extends Node { @Column(name = "FolderID") @Id @GeneratedValue(strategy = GenerationType.AUTO) private long id; @OneToMany(cascade = CascadeType.ALL, mappedBy = "parent", fetch = FetchType.LAZY, orphanRemoval = true) private Set&lt;Node&gt; children = new HashSet&lt;Node&gt;(); public FolderNode() { } public FolderNode(String name) { super(name); } public Set&lt;Node&gt; getChildren() { return children; } public void setChildren(Set&lt;Node&gt; children) { this.children = children; } public long getId() { return id; } public void setId(long id) { this.id = id; } } </code></pre> <h2>Calling code</h2> <pre><code>//Init EntityManagerFactory emf = Persistence.createEntityManagerFactory("database.odb"); EntityManager em = emf.createEntityManager(); //Create object FolderNode rootFolder = new FolderNode("root"); //Persist em.getTransaction().begin(); em.persist(rootFolder); em.getTransaction().commit(); em.close(); emf.close(); emf = Persistence.createEntityManagerFactory("database.odb"); em = emf.createEntityManager(); TypedQuery&lt;FolderNode&gt; query = em.createQuery("SELECT f FROM Folders f", FolderNode.class); List&lt;FolderNode&gt; result = query.getResultList(); </code></pre> <p>And that's where it crashes with an exception:</p> <pre><code>[ObjectDB 2.3.5_07] javax.persistence.PersistenceException Failed to write the value of field field FolderNode.children using reflection (error 363) </code></pre> <p>The problem seems to go away if I don't close and reopen the EntityManagerFactory and EntityManager before fetching the object.</p> <p>What am I missing here?</p>
 

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