Cannot load JDBC driver class 'oracle.jdbc.OracleDriver'
As per Let's Start chapter of JMeter Getting Started Guide
If you want to perform JDBC testing, then you will, of course, need the appropriate JDBC driver from your vendor. JMeter does not come with any JDBC drivers.
And don't forget to restart JMeter to pick the .jar up.
Also change "Validation Query" in the JDBC Connection Configuration to
select 1 from dual
More information: The Real Secret to Building a Database Test Plan With JMeter
Copy the jars you want to use and drop in this location:
Then restart jmeter.