<Context shallowOutput="true" path="/">
<WatchedResource>WEB-INF/web.xml</WatchedResource>

  <Resource name="jdbc/myDataSource"
        auth="Container"
        type="javax.sql.DataSource"
        factory="org.apache.commons.dbcp.BasicDataSourceFactory"
        driverClassName="oracle.jdbc.driver.OracleDriver"
        username="OMITTED"
        password="OMITTED"
        url="OMITTED"
        maxActive="20"
        maxIdle="10"
        maxWait="-1"/>

String db_class = DriverManager.getConnection(db_url, usr, passwd).getClass().getName();

org.postgresql.jdbc4.Jdbc4Connection

ds.getConnection().getClass().getName()

public static void show_connection_info(Connection conn)
    {
    System.out.println("Connection: " + conn);
    System.out.println("Connection class: " + conn.getClass());
    System.out.println("Connection class name: " + conn.getClass().getName());
    }

Connection: oracle.jdbc.driver.T4CConnection@1e1c66a
Connection class: class oracle.jdbc.driver.T4CConnection
Connection class name: oracle.jdbc.driver.T4CConnection

Field field = dataSource.getClass().getDeclaredField("driver");
field.setAccessible(true);
return field.get(dataSource).getClass().getName();

DriverManager.getDriver(ds.getConnection().getMetaData().getURL()).getClass();

if(source instanceof org.apache.tomcat.dbcp.dbcp.BasicDataSource){
    logger.info("Driver className: "+((org.apache.tomcat.dbcp.dbcp.BasicDataSource)source).getDriverClassName());
}

<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-dbcp -->
<dependency><!-- to check driver name effectively running -->
        <scope>provided</scope>
        <groupId>org.apache.tomcat</groupId>
        <artifactId>tomcat-dbcp</artifactId>
        <version>7.0.47</version>
</dependency>