Oracle complains again - Shutting down or initialisation in progress

Problem:
Sometimes Oracle simply flashes the following message or something similar.
Shutting down or initialization in progress.

There's nothing you could do, even after u waited for ages for it to complete its cycle.

Solution:
This is unorthodox, but me being bad programmer, i choose to solve the problem first before looking for detailed explanations.

Log in under SQLPlus with following command.
sqlplus sys/yourpassword as sysdba

Then run the following SQLPLUS commands.
shutdown immediate;
startup;

Sometimes of order of the SQLPlus command needs to be reverse, depending on its state.