NamingException: Cannot create resource instance with tomcat7-maven-plugin h2/mysql database

I'm trying to create maven web application project that makes standalone executable jar when packaging and for that purpose I'm using tomcat7-maven-plugin. The initial hello world kind of application works fine, but I'm struggling to make it work with database. Here is how my pom.xml looks like:

<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.0</version>
<executions>
    <execution>
        <id>tomcat-run</id>
        <goals>
            <goal>exec-war-only</goal>
        </goals>
        <phase>package</phase>
        <configuration>
            <contextFile>src/main/resources/tomcat/context.xml</contextFile>
            <path>/helloworld</path>
            <enableNaming>true</enableNaming>
            <finalName>standalone.jar</finalName>
            <charset>utf-8</charset>
        </configuration>
    </execution>
</executions>
<dependencies>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.183</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.34</version>
    </dependency>
</dependencies>

src/main/webapp/WEB-INF/web.xml:

<web-app>
...
<servlet>
        <servlet-name>TestServlet</servlet-name>
        <servlet-class>com.mycompany.test.TestServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>TestServlet</servlet-name>
        <url-pattern>/helloworld</url-pattern>
    </servlet-mapping>
    <resource-ref>
        <description>H2 DS</description>
        <res-ref-name>jdbc/H2DB</res-ref-name>
        <res-type>org.apache.tomcat.jdbc.pool.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>
    <resource-ref>
        <description>Mysql DS</description>
        <res-ref-name>jdbc/TestDB</res-ref-name>
        <res-type>org.apache.tomcat.jdbc.pool.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>
...
</web-app>

src/main/resources/tomcat/context.xml

<Context path="/helloworld">
    <Resource type="org.apache.tomcat.jdbc.pool.DataSource"
        name="jdbc/H2DB"
        factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
        driverClassName="org.h2.Driver"
        url="jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1"
        username="testuser"
        password="testpassword"
        initialSize="5"
        maxActive="10"
        maxIdle="5"
        minIdle="2"
    />
    <Resource name="jdbc/TestDB" auth="Container" type="org.apache.tomcat.jdbc.pool.DataSource"
        url="jdbc:mysql://localhost:3306/testdb"
        username="testuser" 
        password="testpassword" 
        driverClassName="com.mysql.jdbc.Driver"
        initialSize="5"
        maxActive="10"
        maxIdle="5"
        minIdle="2"
    />
</Context>

and in my java code I'm trying:

Context ctx = new InitialContext();
DataSource ds = (DataSource) ctx.lookup("java:/comp/env/jdbc/TestDB");

or java:/comp/env/jdbc/H2DB for the h2 database Both ways I'm getting the same exception when tomcat is starting my servlet:

SEVERE: Servlet /helloworld threw load() exception javax.naming.NamingException: Cannot create resource instance at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:146) at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source) at org.apache.naming.NamingContext.lookup(NamingContext.java:843) at org.apache.naming.NamingContext.lookup(NamingContext.java:154) at org.apache.naming.NamingContext.lookup(NamingContext.java:831) at org.apache.naming.NamingContext.lookup(NamingContext.java:154) at org.apache.naming.NamingContext.lookup(NamingContext.java:831) ...

I'll be grateful for any ideas. Thanks in advance.

Solved the problem by adding mysql-connector-java as to the tomcat7-maven-plugin's configuration as described here.