A better approach is to do it all via
JDBC. You can pass in the SQL commands via a properties file or XML configuration file. XML is probably a better mechanism in the long run, since it gives you the most flexibility.
SQL*PLUS commands can be found somewhere on the ORACLE website under documentation.
Executing a script outside the VM is not a recommend practice, since it ties you to a particular platform. What would happen if you tried to execute SQL*PLUS and it wasn't pathed correctly? Then you wouldn't have any tables created.
I would put in the work and make it all work inside your application.
my 2c.
-Peter