How the datanucleus tool to run the files for enhancement?

For to enhance the classes and to make normal Java classes "persistable", I have used DataNucleus Enhancer. The issue I am having is: No files to run datanucleus tool (error log shown below) and because of that datanucleus is not enhancing the classes. How the datanucleus run the files for enhancement?

Pom.xml

Dependencies of datanucleus

        <dependency>
            <groupId>org.datanucleus</groupId>
            <artifactId>datanucleus-api-jdo</artifactId>
            <version>4.0.5</version>
           <!--<scope>compile</scope> -->
        </dependency>

        <dependency>
            <groupId>org.datanucleus</groupId>
            <artifactId>datanucleus-core</artifactId>
            <version>4.0.6</version>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.datanucleus</groupId>
            <artifactId>datanucleus-rdbms</artifactId>
            <version>4.0.9</version>
            <scope>runtime</scope>
        </dependency>

Datanucleus Plugin for enhance

            <plugin>
                <groupId>org.datanucleus</groupId>
                <artifactId>datanucleus-maven-plugin</artifactId>
                <version>5.2.1</version>
                <configuration>
                    <api>JDO</api>
                    <persistenceUnitName>MyUnit_Example</persistenceUnitName> <!-- todo: change persistance name-->                   
                    <log4jConfiguration>${pom.basedir}/data/log4j.properties</log4jConfiguration>
                    <generateConstructor>true</generateConstructor>
                    <verbose>true</verbose>
                    <alwaysDetachable>true</alwaysDetachable>
                    <metadataIncludes>${pom.basedir}/dir_name_1/dir_name_2/model**/*.class</metadataIncludes>
                </configuration>
                <executions>
                    <execution>
                        <phase>process-classes</phase>
                        <goals>
                            <goal>enhance</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

Warning list

[INFO] --------------------------------[ jar ]---------------------------------
[WARNING] The POM for org.mortbay.jetty:servlet-api:jar:2.5-6.0.0beta12 is missing, no dependency information available
[INFO] 
[INFO] --- datanucleus-maven-plugin:5.2.1:enhance (default-cli) @ forsteinrichtung ---
[WARNING] No files to run DataNucleus tool 'org.datanucleus.enhancer.DataNucleusEnhancer'

My setup for enhance the classes, I hope it could help you to find a solution. You need to add a persistence.xml, update the Datanucleus dependency artifact versions and add a dependency of javax.jdo for datanuclues which provides an interface to java model abstraction for persistence.

pom.xml

Depandancy for Datanucleus

<dependency>
    <groupId>org.datanucleus</groupId>
    <artifactId>datanucleus-api-jdo</artifactId>
    <version>5.2.7</version>
    <scope>compile</scope>
</dependencies>

<dependency>
    <groupId>org.datanucleus</groupId>
    <artifactId>datanucleus-core</artifactId>
    <version>5.2.9</version>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>org.datanucleus</groupId>
    <artifactId>datanucleus-rdbms</artifactId>
    <version>5.2.9</version>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>org.datanucleus</groupId>
    <artifactId>javax.jdo</artifactId>
    <version>3.2.0-m11</version>
</dependency>

Datanucleus Plugin for enhance

  <plugin>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-maven-plugin</artifactId>
        <version>5.2.1</version>
        <configuration>
            <api>JDO</api>
            <persistenceUnitName>h2</persistenceUnitName>
            <log4jConfiguration>${project.basedir}/data/config/log4j.properties</log4jConfiguration>
            <verbose>true</verbose>
            <fork>false</fork>
        </configuration>
        <dependencies>
            <dependency>
                <groupId>org.datanucleus</groupId>
                <artifactId>datanucleus-core</artifactId>
                <version>5.2.9</version>
                <scope>runtime</scope>
            </dependency>
        </dependencies>
        <executions>
            <execution>
                <phase>process-classes</phase>
                <goals>
                    <goal>enhance</goal>
                </goals>
            </execution>
        </executions>
    </plugin>

persistence.xml

The location for persistence.xml is "resources > META-INF > persistence.xml". If persistence.xml does not exist then one need to create new persistence.xml.

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
         version="2.0">
<persistence-unit name="h2" transaction-type="RESOURCE_LOCAL">
    <properties>
        <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:test" />
        <property name="javax.persistence.jdbc.driver" value="org.h2.Driver" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
        <property name="hibernate.format_sql" value="true" />
        <property name="hibernate.show_sql" value="true" />
        <property name="javax.persistence.schema-generation.database.action" value="create"/>
        <property name="javax.persistence.schema-generation.create-source" value="script"/>
        <property name="javax.persistence.schema-generation.create-script-source" value="sql/create.sql"/>
        <!--<property name="javax.persistence.schema-generation.drop-source" value="script"/> -->
        <!--<property name="javax.persistence.schema-generation.drop-script-source" value="sql/drop.sql"/> -->
        <property name="javax.persistence.sql-load-script-source" value="sql/initial_data.sql" />
        <property name="javax.persistence.jdbc.user" value="sa"/>
        <property name="javax.persistence.jdbc.password" value="sa"/>
    </properties>
</persistence-unit>