[Enhancement] Name the ' db.lck' file within a booted db to be '.db.lck'

[Rajesh Kartha]

Hi,

I was wondering, if we could  name the 'db.lck' file within a Derby 
database  to be '.db.lck'  to indicate the db has been booted.

By appending a '.' before the file name most of the OSes will consider 
it as a hidden file and will not show
in the default directory listing unless an 'ls -a' is used. This can 
avoid unwanted/accidental deletion of this file on Linux/Unix.

I will open a JIRA enhancement request to track this.

Regards,
Rajesh