How to restore the offline backup

dear sir/mam,

kindly assist how to restore the backup 

An ObjectDB backup is a valid database itself. Just replace the database file with the backup file.

the file which is used by the database is not replacing as it is currently in use

now how can i replace the backup file with the previously used file which is in use ?

kindly help !!!

Close all connection to the database (close the EntityManagerFactory), restore, open it again.