Tomcat 8: determine connection pool

Question

In my context.xml for Tomcat 8 (Debian) I define the following resource:

<Context>
...
<Resource auth="Container"
          name="jdbc/UPAY"
          type="javax.sql.DataSource"
          maxTotal="100"
          maxIdle="30"
          maxWaitMillis="10000"
          username="root" password="changeit"
          driverClassName="com.mysql.jdbc.Driver"
          url="jdbc:mysql://localhost/UPAY"
          validationQuery="select 1"/>
...
</Context>

I am however not clear which DB pool implementation will be used:

• https://tomcat.apache.org/tomcat-8.0-doc/jdbc-pool.html
• http://commons.apache.org/proper/commons-dbcp/
• other?

How can I determine, which database pool is used by tomcat 8? Is there a Java API so that I can do this programmatically?