Oracle : How to query a holding lock in your oracle database

ever wonder why can't you compile your procedure,function or package and if you look at the database for locks you could not find one, well maybe there is a holding lock in your object that you are trying to compile or edit. One way to know this is by issuing the sql statement below, you will see who is waiting(session) for that object and who is holding(session) for that object.

select /*+ ordered */ w1.sid waiting_session,
h1.sid holding_session,
w.kgllktype lock_or_pin,
w.kgllkhdl address,
decode(h.kgllkmod, 0, 'None', 1, 'Null', 2, 'Share', 3, 'Exclusive',
'Unknown') mode_held,
decode(w.kgllkreq, 0, 'None', 1, 'Null', 2, 'Share', 3, 'Exclusive',
'Unknown') mode_requested
from dba_kgllock w, dba_kgllock h, v$session w1, v$session h1
where
(((h.kgllkmod != 0) and (h.kgllkmod != 1)
and ((h.kgllkreq = 0) or (h.kgllkreq = 1)))
and
(((w.kgllkmod = 0) or (w.kgllkmod= 1))
and ((w.kgllkreq != 0) and (w.kgllkreq != 1))))
and w.kgllktype = h.kgllktype
and w.kgllkhdl = h.kgllkhdl
and w.kgllkuse = w1.saddr
and h.kgllkuse = h1.saddr;

if this query returned some rows then it is up to you to identify which SID to kill