Trying to connect with a wrong username or password returns an SQLException which does not contain the correct expected error code (1045).

Trying with command line:
>mysql -u bar -pfoo testdb
ERROR 1045 (28000): Access denied for user 'bar'@'localhost' (using password: YES)

Using the attached test program reproduces the error:

Output MariaDB connector
MariaDB Exception: java.sql.SQLException: Could not connect: Access denied for user 'foo'@'localhost' (using password: YES)
MariaDB ErrorCode: -1
MariaDB SQLState: HY0000

Output MySQL connector
MySQL Exception: java.sql.SQLException: Access denied for user 'foo'@'localhost' (using password: YES)
MySQL ErrorCode: 1045
MySQL SQLState: 28000

-> We need this error code in order to be able to detect if a connection is setup using a wrong username or password.