Datanucleus + Maven: cannot find main class SchemaTool - maven

Question

I am trying to make a maven project using Datanucleus as a database abstraction. However, when i try to mvn datanucleus:schema-create, i get the following error:
[ERROR] --------------------
[ERROR] Standard error from the DataNucleus tool + org.datanucleus.store.schema.SchemaTool :
[ERROR] --------------------
[ERROR] Error: Could not find or load main class org.datanucleus.store.schema.SchemaTool
The relevant parts from the pom.xml file are:
<dependencies>
<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>4.0.4</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-api-jdo</artifactId>
<version>4.0.4</version>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-rdbms</artifactId>
<version>4.0.4</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<!-- <version>3.2</version> -->
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-maven-plugin</artifactId>
<version>4.0.0-release</version>
<configuration>
<api>JDO</api>
</configuration>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
And the persistence.xml file is in /src/main/resources/META-INF/persistence.xml, containing the following:
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<!-- JDO tutorial "unit" -->
<persistence-unit name="Tutorial">
<class>a.b.c.MyClass</class>
<exclude-unlisted-classes />
<properties>
<property name="javax.jdo.option.PersistenceUnitName" value="Tutorial" />
<property name="javax.jdo.option.ConnectionURL" value="jdbc:mysql://localhost/mydb" />
<property name="javax.jdo.option.ConnectionDriverName"
value="com.mysql.jdbc.Driver" />
<property name="javax.jdo.option.ConnectionUserName" value="myuser" />
<property name="javax.jdo.option.ConnectionPassword" value="mypass" />
<property name="datanucleus.schema.autoCreateAll" value="true" />
<property name="datanucleus.schema.validateTables" value="true" />
<property name="datanucleus.schema.validateConstraints"
value="true" />
<property name="javax.jdo.PersistenceManagerFactoryClass"
value="org.datanucleus.api.jdo.JDOPersistenceManagerFactory" />
</properties>
</persistence-unit>
To my untrained eye it looks like everything is in place, yet it doesn't work.

Answer 1

Perhaps your <scope>runtime</scope> is causing the problem, because that jar contains this class. Whether it is or not you can easily enable Maven debug --debug on the command line and look at what is in the CLASSPATH for that operation.