Configure Apache dbcp2 connection pool in tomcat 7.x

Question

I am working on a legacy application that uses Tomcat 7.0.64 and we want to configure apache dbcp2 connection pool as a resource in Tomcat. The application runs Spring 4.x and Hibernate 4.x. After reading Tomcat documentation when I try to access the dbcp2 connection pool from Spring application I am getting the following exception -

javax.naming.NamingException: Could not create resource factory instance [Root exception is java.lang.ClassNotFoundException: org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory]

Why is org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory being used even though the "factory" attribute added in server.xml is of type org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory. Below mentioned are the details of the configurations -

Added following in server.xml -

<GlobalNamingResources>
    <Resource name="jdbc/mytestDB"
    auth="Container"
    factory="org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory"
    type="javax.sql.DataSource"
    username="test"
    password="test"
    driverClassName="oracle.jdbc.driver.OracleDriver"
    description="test db"
    url="jdbc:oracle:thin:@mytestDB:1521/mytestDB"
    maxActive="15"
    maxIdle="5"/>
</GlobalNamingResources>

Added following in web.xml -

 <resource-ref>
     <description>PVO Database</description>
     <res-ref-name>jdbc/mytestDB</res-ref-name>
     <res-type>javax.sql.DataSource</res-type>
     <res-auth>Container</res-auth>
 </resource-ref>

Added following maven dependencies -

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-dbcp2</artifactId>
    <version>2.8.0</version>
</dependency>           

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-dbcp</artifactId>
<version>8.5.4</version>
</dependency>           
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.8.1</version>
</dependency>

In test class added the following -

Context initContext = new InitialContext(); 
Context envContext = (Context)initContext.lookup("java:comp/env");
DataSource ds = envContext.lookup("jdbc/mytestDB"); // This line gives the above mentioned error.    
Connection connection = ds != null ? ds.getConnection() : null;

Answer 1

Fixed the issue by adding the following JVM property in tomcat -configure data sources to be retrieved via JNDI -

JAVA_OPTS="${JAVA_OPTS} -

Djavax.sql.DataSource.Factory="org.apache.commons.dbcp2.BasicDataSourceFactory"

However we decided to upgrade tomcat version.