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POCollection not loaded if bean was loaded before as relation
 

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  1. POCollection not loaded if bean was loaded before as relation
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    <p>I have the classes A, B and C. A has a property to B (manytoone) and B has a property to C (onetomany). The classes look like the following ones (shortend to the relevant properties):</p> <pre><code>class A { [...] @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "fkb", nullable = false) private B b; [...] } class B { [...] @OneToMany(mappedBy = "b") @Cascade(value = { CascadeType.ALL }) private Set&lt;C&gt; cs; public Set&lt;C&gt; getCs() { return cs; } [...] } class C { @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "fkb", nullable = false) private B b; } </code></pre> <p>The problem is now that depending on the order in which i load As and Bs the collection of Cs in B doesn't work anymore:</p> <pre><code>// outputs correct count of Cs per B List&lt;B&gt; bs = session.createCriteria(B.class).list(); for (B b : bs) { System.out.println(b.getCs().size()); } // outputs always 0 List&lt;A&gt; as = session.createCriteria(A.class).list(); List&lt;B&gt; bs = session.createCriteria(B.class).list(); for (B b : bs) { System.out.println(b.getCs().size()); } </code></pre> <p>The following debugging i have already done:</p> <ul> <li>In the second code hibernate triggers no select statements to load Cs</li> <li>In the first code the returned Bs are of type B and the Set of Cs has type org.hibernate.collection.PersistentSet</li> <li>In the second code the returned Bs are of type B_$$_javassist_58 and the Set of Cs has type java.util.HashSet</li> </ul> <p>I am using Hibernate 3.8.3.</p>
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USZaki
    1. USWerzi2001
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
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      1. POCollection not loaded if bean was loaded before as relation
      1. USWerzi2001
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    2. VO
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      1. POCollection not loaded if bean was loaded before as relation
      1. This table or related slice is empty.
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    3. VO
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      1. POCollection not loaded if bean was loaded before as relation
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIf you don't load A at all do the problem persists ? In the second code it's ok that B is of type "javassist" because it is a proxy but it's strange that your Set<C> is a HashSet if it was loaded by Hibernate.
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      1. POCollection not loaded if bean was loaded before as relation
      1. USJulien Bodin
    2. COIf i don't load As the problem doesn't occur (this is the first code example). The problem only occurs if As were loaded before Bs.
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      1. POCollection not loaded if bean was loaded before as relation
      1. USWerzi2001
    3. COWhat happens if you don't ask the size but instead do a foreach on b.getCs() and print some variable from your c instance ? (yes it's strange but you know, with Hibernate... :D)
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      1. POCollection not loaded if bean was loaded before as relation
      1. USJulien Bodin
 

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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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