Lazy loading of @ManyToOne relation fails with GlassFish 4 / EclipseLink

Question

GlassFish 4 (actually its JPA implementation, i.e. EclipseLink) fails to lazy load a @ManyToOne JPA relation from our Java EE 7 application. Default/eager loading is ok, but not lazy loading.

The relation in the 'Student' entity is:

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "addr_id")
private Address address;

The (simplified) persistence.xml looks like:

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
             version="2.1">
    <persistence-unit name="foo-PU" transaction-type="JTA">
        <jta-data-source>jdbc/foo-DS</jta-data-source>
        <class>foo.domain.Student</class>
        <class>foo.domain.Address</class>
        <exclude-unlisted-classes>true</exclude-unlisted-classes>
        <properties>
            <property name="eclipselink.target-database" value="PostgreSQL"/>
            <property name="eclipselink.logging.level" value="FINE"/>
        </properties>
    </persistence-unit>
</persistence>

The application uses several API: PrimeFaces, JSF 2.2, CDI 1.1, JPA 2.1.

Also note that the EntityManager are not obtained by injection into session EJB, but manually created using Persistence.createEntityManagerFactory(...) then emf.createEntityManager(...).

The error message is:

WARNING:   Reverting the lazy setting on the OneToOne or ManyToOne attribute [address] for the entity class [class foo.domain.Student] since weaving was not enabled or did not occur.

My understanding is that, for some reason, the dynamic weaving of entities is not enabled. For a Java EE application it should be, as suggested by http://wiki.eclipse.org/EclipseLink/UserGuide/JPA/Advanced_JPA_Development/Performance/Weaving.

For the record, if we try to force the weaving using this:

<property name="eclipselink.weaving" value="true"/>

in the persistence.xml, then we get another error message:

SEVERE:   Error Rendering View[/student/studentList.xhtml]
javax.el.ELException: /student/studentList.xhtml @24,81 value="#{studentController.selectedCode}": Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: WebappClassLoader (delegate=true; repositories=WEB-INF/classes/)
Internal Exception: javax.persistence.PersistenceException: Exception [EclipseLink-28022] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Value [true] for the property [eclipselink.weaving] is incorrect when global instrumentation is null, value should either be null, false, or static.
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIOutput.getValue(UIOutput.java:174)
at javax.faces.component.UIInput.getValue(UIInput.java:291)
at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
(...)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)

Any idea how to fix this lazy-loading issue? Why is the dynamic weaving not enabled by default ?

Thanks.

Why are you using a JTA datasource etc but obtaining the EMF from the Persistence class as if it were a java SE application? From the sounds of it, the container is not deploying the persistence unit - this is required for the container to hook in the agent to weave the classes. You will have to look at how the persistence unit is packaged within the application to determine why this isn't happening, chances are it is just packaged incorrectly or a resource reference is missing. — Chris, Sep 13 '13 at 15:25
JPA does not support multitenancy, so we manually create the EMF and EM to be able to dynamically bind them to the right datasource. This works fine with many app servers. We also use JTA data sources to support distributed transactions. These choices should not have impacts on the issue we meet. Now the other persistence operations work fine (read, find, update, ...), so the persistence unit configuration should be fine. Also the GlassFish logs do not mention other problems, I can see the PU being initialized. — Florian Beaufumé, Sep 14 '13 at 08:21
We are experiencing the same problem. Did you ever resolve this issue? — bdrx, Aug 28 '14 at 18:48

slavik · Answer 1 · 2020-08-01T10:52:50.670

If you set eclipselink.weaving to true it means that you want to weave an entity classes dynamically. To make this work you need to run a jvm with a proper javaagent. First download an agent

wget -O /tmp/eclipselink.jar \
https://repo1.maven.org/maven2/org/eclipse/persistence/eclipselink/2.7.7/eclipselink-2.7.7.jar

and then run your app using following snippet

java -javaagent:/tmp/eclipselink.jar ....

But if you set eclipselink.weaving to static then you inform jpa that you want to weave the entity classes statically. Of course you have to trigger the waving by your own for example using this maven plugin https://github.com/craigday/eclipselink-staticweave-maven-plugin

Lazy loading of @ManyToOne relation fails with GlassFish 4 / EclipseLink

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