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POJSF and JPA with @ManyToMany and custom converter: LazyInitializationException
 

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    <p>I have an <code>@Entity</code> with :</p> <pre><code>@Entity public class Issue implements Serializable { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) protected long id; @ManyToOne private IssueScope scope; //getter/setter } </code></pre> <p>I use the custom <code>IssueScopeConverter</code> to directly use the <code>IssueScope</code> with <em>f:selectItems</em>. The converter simply</p> <ul> <li>returns the <em>id</em> for the method <code>getAsString</code></li> <li>return a newly created object <code>IssueScope</code> (with <em>id</em> set) for <code>getAsObject</code></li> </ul> <p>This does not raise any problems (and is used many times before with <code>@ManyToOne</code>) with <em>p:selectOneMenu</em> and similar components with code like this:</p> <pre><code>&lt;h:form id="fScope"&gt; &lt;p:selectOneButton rendered="true" value="#{issueBean.issue.scope}" converter="IssueScopeConverter"&gt; &lt;f:selectItems value="#{issueBean.issueScopes}" var="s" itemLabel="#{s.name}" itemValue="#{s}"/&gt; &lt;/p:selectOneButton&gt; &lt;p:commandButton value="Save" actionListener="#{issueBean.save()}"/&gt; &lt;/h:form&gt; </code></pre> <p>Now let's describe my problem: In fact I don't need a <code>@ManyToOne</code>, I need a <code>@ManyToMany</code> relationship from <code>Issue</code> to <code>IssueScope</code>:</p> <pre><code>@ManyToMany(fetch=FetchType.EAGER) private List&lt;IssueScope&gt; scopes; </code></pre> <p>and the XHTML will change to this:</p> <pre><code>&lt;h:form id="fScopes"&gt; &lt;p:selectManyCheckbox value="#{issueBean.issue.scopes}" converter="ErpIssueScopeConverter"&gt; &lt;f:selectItems value="#{issueBean.issueScopes}" var="s" itemLabel="#{s.name}" itemValue="#{s}"/&gt; &lt;/p:selectManyCheckbox&gt; &lt;p:commandButton value="Save" actionListener="#{issueBean.save()}"/&gt; &lt;/h:form&gt; </code></pre> <p>If I newly create <code>Issue</code> and then push the <em>Save</em> button to persist the entity this is done without exception. Even selected <code>IssueScopes</code> are persisted. Then, if I want to update the entity, I get a <code>failed to lazily initialize a collection, no session or session was closed: org.hibernate.LazyInitializationException: failed to lazily initialize a collection, no session or session was closed</code> after pushing the button.</p> <p>The method <code>public void save()</code> in my <code>@Named @ViewScoped IssueBean</code> is never entered.</p> <p>The problem seems to be related to <a href="https://stackoverflow.com/questions/9886390/lazy-loading-exception-when-using-jsf-converter-refering-to-a-collection">Lazy loading exception when using JSF Converter (refering to a collection)</a>, but I don't use Seam persistence or have special kind of TransactionInterceptor`. </p>
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