Check locked object

1. Check locked object:
selectc.owner, c.object_name,c.object_type, b.sid, b.serial#, b.status, b.osuser, b.machine
from v$locked_object a ,
v$session b,
dba_objects c
where b.sid = a.session_id
and a.object_id = c.object_id;

2. Then use Sid from above queries to see what its doing.
select s.sid, s.username, s.schemaname, s.osuser, s.machine, s.terminal, s.program, sa.sql_text from v$sqlarea sa, v$session s
where s.sql_hash_value = sa.hash_value
and s.sql_address = sa.address
and s.sid=&sid
select sid,username,status,blocking_session,wait_class,seconds_in_wait,state
from v$sessionwhere sid=&sid