query which table is locked

--check lock
SELECT s1.username || '@' || s1.machine || ' ( SID=' || s1.sid ||
       ' )  is blocking ' || s2.username || '@' || s2.machine || ' ( SID=' ||
       s2.sid || ' ) ' AS blocking_status
  FROM v$lock    l1,
       v$session s1,
       v$lock    l2,
       v$session s2
 WHERE s1.sid = l1.sid
   AND s2.sid = l2.sid
   AND l1.BLOCK = 1
   AND l2.request  > 0
   AND l1.id1 = l2.id1
   AND l2.id2 = l2.id2;