That's an interesting question. I'm surprised that nobody has asked it before. The following query will identify all sessions holding object locks:
select a.aw_name,o.obj_name objname, e.sid sess_id from dba_aw_obj o, gv_$enqueue_lock e, dba_aws a where e.type='AO' and o.aw_number=e.id1 and a.aw_number = e.id1 and bitand(o.obj_id, 1073741823) = e.id2;
thanks a lot Jim , I had not seen your answer.