The SQL Agent installation instructions include some cryptic information about the JDBC driver. In light of my findings above, it is interesting to revisit these sections of the documentation:
Copy the file ojdbc5.jar or ojdbc6.jar to the folder's JDBC directory after you have installed the driver.
...
The agent searches the relevant jar-file classes in the JDBC folder. The file name is irrelevant.
This suggests that the name of the JDBC JAR file is actually unimportant, and that the agent looks at the names of the classes (and versions) of the files contained in each JAR file under the jdbc subdirectory.
It is important to use the most current jar file. Store only one jar file in the JDBC folder.
Well, it’s actually more important to use the JAR file that works with the version of Java and Oracle being used. However I actually think this is the author’s rather unusual way of saying that the agent loads the JDBC driver with the highest version.
Having more than one JDBC JAR file in the directory is not a problem in itself.