Tomcat servlet configure JNDI - oracle

Question

Good day, respective all!
My environment:
Tomcat 8.5 under windows 64-bit
All needed jars are placed into $CATALINA_HOME/lib
It is my first attempt to write servlet using ConnectionPool.
After "googling"I made an entry inside $CATALINA_HOME/conf/server.xml:
<context docbase="msgsend" path="/msgsend" reloadable="true">
<context docbase="ssr" path="/ssr" reloadable="true">
<Resource
name="jdbc/OrServlet"
auth="Container"
type="javax.sql.DataSource"
user="STERN"
username="STERN"
password="pwdxxx"
driverClassName="oracle.jdbc.OracleDriver"
url="jdbc:oracle:thin:STERN/pwdxxx#XEPDB1"
/>
</context>
I included following into WEb-INF/web.xml:
<resource-ref>
<description>just a test</description>
<res-ref-name>jdbc/OrServlet</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
When I try to connect to Oracle in traditional way:
try {
cn = DriverManager.getConnection(
"jdbc:oracle:thin:#XEPDB1", "STERN", "pwdxx");
}
catch (Exception e) { }
everything works fine.
But when I try to connect through context:
Connection cn = null;
DataSource ds = null;
try
{
Context initCtx = new InitialContext();
Context envCtx = (Context)initCtx.lookup("java:comp/env");
ds = (DataSource)envCtx.lookup("jdbc/OrServlet");
cn = ds.getConnection();
}
catch(NamingException n) {}
catch(SQLException s) {out.println(ds.getClass().getName()+" exception "+s);
;}
I get :
**exception java.sql.SQLException: Cannot create JDBC driver of class '' for connect URL 'null'**
and ds.getClass().getName() in exception handler returns:
org.apache.tomcat.dbcp.dbcp2.BasicDataSource
which is distinct from javax.sql.DataSource as declared in
and .
And it seems to me that ds = (DataSource)envCtx.lookup("jdbc/OrServlet")
doesn't wvwn try to look inside Resource section.
What I missed?
Any help will be very appreciated.
Regards,
Andrew.