DataNucleus: Tidak ada StoreManager tipe appengine yang tersedia

Saya mencoba menyiapkan instance AppEngine dengan JPA menggunakan DataNucleus. Tapi saya mendapatkan kesalahan berikut saat runtime ketika unit persistensi dimuat:

[INFO] Caused by: java.lang.ExceptionInInitializerError
[INFO]  at org.apache.jsp.guestbook_jsp._jspService(guestbook_jsp.java:123)
[INFO]  ... 45 more
[INFO] Caused by: org.datanucleus.exceptions.NucleusUserException: There is no available StoreManager of type "appengine". Make sure that you have put the relevant DataNucleus store plugin in your CLASSPATH and if defini
ng a connection via JNDI or DataSource you also need to provide persistence property "datanucleus.storeManagerType"
[INFO]  at org.datanucleus.NucleusContext.createStoreManagerForProperties(NucleusContext.java:1276)
[INFO]  at org.datanucleus.NucleusContext.initialise(NucleusContext.java:357)
[INFO]  at org.datanucleus.api.jpa.JPAEntityManagerFactory.initialiseNucleusContext(JPAEntityManagerFactory.java:816)
[INFO]  at org.datanucleus.api.jpa.JPAEntityManagerFactory.initialise(JPAEntityManagerFactory.java:437)
[INFO]  at org.datanucleus.api.jpa.JPAEntityManagerFactory.<init>(JPAEntityManagerFactory.java:396)
[INFO]  at org.datanucleus.api.jpa.PersistenceProviderImpl.createEntityManagerFactory(PersistenceProviderImpl.java:116)
[INFO]  at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
[INFO]  at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)

Kesalahan ini terjadi untuk penerapan lokal dan AppEngine.

Nilai apa yang harus saya berikan untuk properti datanucleus.ConnectionURL bukan AppEngine? NB Saya tidak dapat menemukan dokumen apa pun yang menjelaskan arti sebenarnya dari nilai ini di lingkungan AppEngine. Apa maksudnya menghubungkan?

Apakah saya bermaksud mendefinisikan StoreManager di suatu tempat?

Apakah saya melewatkan beberapa perpustakaan? Jika ya, apa?

Kegigihan saya.xml adalah:

<persistence-unit name="main">
    <provider>org.datanucleus.api.jpa.PersistenceProviderImpl</provider>

    <mapping-file>/META-INF/user.xml</mapping-file>

    <properties>
        <property name="datanucleus.NontransactionalRead" value="true"/>
        <property name="datanucleus.NontransactionalWrite" value="true"/>
        <property name="datanucleus.ConnectionURL" value="appengine"/>

        <!--property name="datanucleus.appengine.datastoreReadConsistency" value="EVENTUAL" /-->
        <!--property name="javax.persistence.query.timeout" value="5000" /-->
        <!--property name="datanucleus.datastoreWriteTimeout" value="10000" /-->
        <property name="datanucleus.singletonEMFForName" value="true"/>
    </properties>
</persistence-unit>

Ketergantungan di POM saya adalah: com.google.appengine appengine-api-1.0-sdk ${appengine.target.version}

    ..

    <!-- Persistence APIs -->
    <dependency> <!-- why do I need this if I am using JPA? -->
        <groupId>javax.jdo</groupId>
        <artifactId>jdo-api</artifactId>
        <version>3.0.1</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>javax.persistence</artifactId>
        <version>2.1.0</version>
    </dependency>
    <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-core</artifactId>
        <version>[3.2.0, 3.2.99)</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-api-jpa</artifactId>
        <version>[3.3.0-release, 3.3.99)</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-rdbms</artifactId>
        <version>[3.2.0, 3.2.99)</version>
        <scope>runtime</scope>
    </dependency>
</dependencies>

Dan plugin datanucleusnya adalah:

    <plugin>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-maven-plugin</artifactId>
        <version>3.3.0-release</version>
        <configuration>
            <api>JPA</api>
            <persistenceUnitName>main</persistenceUnitName>
            <verbose>true</verbose>
        </configuration>
        <executions>
            <execution>
                <phase>process-classes</phase>
                <goals>
                    <goal>enhance</goal>
                </goals>
            </execution>
        </executions>
        <dependencies>
            <dependency>
                <groupId>org.datanucleus</groupId>
                <artifactId>datanucleus-core</artifactId>
                <version>[3.2.0, 3.2.99)</version>
            </dependency>
            <dependency>
                <groupId>org.datanucleus</groupId>
                <artifactId>datanucleus-api-jpa</artifactId>
                <version>[3.3.0-release, 3.3.99)</version>
            </dependency>
        </dependencies>
    </plugin>