App Engine, JDO and Maven. Error on startup - google-app-engine

Question

I'm trying to create a simple test using JDO with App Engine and a Maven configuration.
My compile and data enhancement steps succeed. But at runtime (both mvn:test and appengine:devserver) I get:
1) Error in custom provider, javax.jdo.JDOFatalInternalException:
Class "com.google.appengine.datanucleus.DatastoreManager" was not found in the CLASSPATH.
Please check your specification and your CLASSPATH.
However, my classpath (target/demo/WEB-INF/lib) does contain: datanucleus-appengine-2.1.1.jar
And my dependencies are the same as those specified in the Google datanucleus project's POM:
<dependency>
<groupId>javax.jdo</groupId>
<artifactId>jdo-api</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-core</artifactId>
<version>[3.1.1, 3.2)</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-api-jdo</artifactId>
<version>[3.1.1, 3.2)</version>
</dependency>
<dependency>
<groupId>com.google.appengine.orm</groupId>
<artifactId>datanucleus-appengine</artifactId>
<version>2.1.1</version>
</dependency>
Appreciate any suggestions.
RB

Answer 1

I have everything working now. I thought I'd share a couple of the gotchas (since it took me several days to plough through all of this):
1). All of the versions really matter (esp. matching the App Engine ORM 2.1.1 to DataNucleus 3.1.1 -- including the plugin).
http://www.datanucleus.org/products/accessplatform_3_2/datastores/appengine.html
Here's what I ended up with:
<dependency>
<groupId>javax.jdo</groupId>
<artifactId>jdo-api</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-core</artifactId>
<version>3.1.1</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-api-jdo</artifactId>
<version>3.1.2</version>
</dependency>
<dependency>
<groupId>com.google.appengine.orm</groupId>
<artifactId>datanucleus-appengine</artifactId>
<version>2.1.2</version>
</dependency>
...
<plugin>
<groupId>org.datanucleus</groupId>
<artifactId>maven-datanucleus-plugin</artifactId>
<version>3.1.2</version>
<configuration>
<log4jConfiguration>${basedir}/log4j.properties</log4jConfiguration>
<verbose>false</verbose>
<fork>false</fork>
</configuration>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
</plugin>
2). Check the tail of the datanucleus.log to confirm that your classes were enhanced (via mvn datanucleus:enhance). I eventually realized that my test classes (in src/test) were being ignored.

Answer 2

I have added false in pom.xml and it works for me
<plugins>
<plugin>
<groupId>org.datanucleus</groupId>
<artifactId>maven-datanucleus-plugin</artifactId>
<version>3.1.2</version>
<configuration>
**<fork>false</fork>**
<log4jConfiguration>${basedir}/log4j.properties</log4jConfiguration>
<verbose>true</verbose>
</configuration>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>