How find by who the objects is locked
SELECT s.sid,
s.username
FROM v$lock l,
dba_objects o,
v$session s
WHERE l.id1 = o.object_id
AND s.sid = l.sid
AND o.object_name = 'OBJECT_NAME';
SELECT s.sid,
s.username
FROM v$lock l,
dba_objects o,
v$session s
WHERE l.id1 = o.object_id
AND s.sid = l.sid
AND o.object_name = 'OBJECT_NAME';