Query to find locked objects in Oracle

Sometimes program takes a little longer time then expected, one of the reason to this could be that the table/object you are trying to manipulate is locked by other program and hence it is waiting for the resource to be released.
Below query can be handy to find the objects that are locked

SELECT   c.owner
       , c.object_name
       , c.object_type
       , b.SID
       , b.serial#
       , b.status
       , b.osuser
       , b.machine
       , b.program
       , b.module
       , b.action
FROM     v$locked_object a
       , v$session b
       , dba_objects c
WHERE    b.SID = a.session_id 
AND a.object_id = c.object_id
ORDER BY module

If you want to forcefully kill any session then it can be done using

alter system kill session 'sid,serial#'

e.g. 
altery system kill session '123,5325'