I downloaded the jar of Core Apache Derby database engine, which also includes the embedded JDBC driver (10.9.1.0). But that jar doesn\'t include the .class fil
OK: have you looked on the Apache Derby page:
Download db-derby-10.9.1.0-bin.zip
It contains many files, including derby.jar and derbyclient.jar (along with much documentation).
derbyclient.jar contains our friend org.apache.derby.jdbc.ClientDriver.class