You can kill the session which caused the lock use the command ALTER SYSTEM KILL SESSION 'sid,serial#'
-laotang(laotang);
2001-11-9{229}(#254610@0)
You can get the SID from v$locked_objects,then get SERIAL# from V$SESSION;
If you want to know which table is locked,query V$LOCKED_OBJECTS,
you can get OBJECT_ID, then query DBA_OBJECTS, you can get the table name.
Good Luck!