startup,shutdown and recover commands through JDBC

I got the errors during the excution of the following commands in JDBC

1. Startup ::
For startup command i got the following error "oracle not available"

2. Recover ::
For recovery, the error is "invalid SQL statement"

3.shutdown immediate ::

For shutdown immediate, the error is "invalid SQL statement"

Can i execute these commands from JDBC.
If so, how to execute them

With Regards
Vara Prasad