select object_id,session_id,locked_mode from v$locked_object; 

select t2.username,t2.sid,t2.serial#,t2.logon_time 
  from v$locked_object t1,v$session t2 
  where t1.session_id=t2.sid order by t2.logon_time;


alter system kill session 'sid,serial#'