Hi Ravi,
When do yo create a lock object for table, abap engine create two function modules automatically too. Those function module begin with:
DEQUEUE_lock_object_name
ENQUEUE_lock_object_name
So, if do you want lock your table for write, your have to use CALL FUNCTION 'ENQUEUE_lock_object_name' in you abap code explicity. So, when your write process is finish, your need to use CALL FUNCTION 'DEQUEUE_lock_object_name' in you abap code explicity for free lock object.
Regards,